1990 Census of Population and Housing:

User Guide and Tutorial: Glossaries - Population Variables

APPENDIX B. Definitions of Subject Characteristics

CONTENTS 



POPULATION CHARACTERISTICS                                         B-2 



Ability to Speak English (See Language Spoken at Home and Ability to Speak English) 



  Actual Hours Worked Last Week (See Employment Status) 



  Age                                                              B-2 



  American Indian Tribe (See Race) 



  Ancestry                                                         B-2 



  Carpooling (See Journey to Work) 



  Children Ever Born (See Fertility) 



  Citizenship                                                      B-4 



  Civilian Labor Force (See Employment Status) 



  Class of Worker (See Industry, Occupation, and Class of Worker) 



  Disability (See Mobility Limitation Status, see Self-Care Limitation Status, see 

    Work Disability Status)



  Earnings in 1989 (See Income in 1989) 



  Educational Attainment                                           B-4 



  Employment Status                                                B-5



  Families (See Household Type and Relationship) 



  Family Composition (See Household Type and Relationship) 



  Family Income in 1989 (See Income in 1989) 



  Family Size (See Household Type and Relationship) 



  Family Type (See Household Type and Relationship) 



  Farm Population (See Farm Residence under Housing Characteristics) 



  Fertility                                                        B-7 



  Foreign-Born Persons (See Place of Birth) 



  Foster Children (See Household Type and Relationship) 



  Group Quarters                                                   B-7 



  Hispanic Origin                                                  B-12 



  Household (See Household Type and Relationship) 



  Household Income in 1989 (See Income in 1989) 



  Household Language (See Language Spoken At Home and Ability

   to Speak English) 



  Household Size (See Household Type and Relationship) 



  Household Type and Relationship                                  B-13 



  Householder (See Household Type and Relationship) 



  Income Deficit (See Income in 1989) 



  Income in 1989                                                   B-15 



  Income Type in 1989 (See Income in 1989) 



  Industry, Occupation, and Class of Worker                        B-19 



  Institutionalized Persons (See Group Quarters) 



  Journey to Work                                                  B-21 



  Labor Force Status (See Employment Status) 



  Language Spoken at Home and Ability to Speak English             B-23 



  Linguistic Isolation (See Language Spoken at Home and Ability

   to Speak English) 



  Marital Status                                                   B-25 



  Married Couples (See Marital Status) 



  Means of Transportation to Work (See Journey to Work) 



  Migration (See Residence in 1985) 



  Mobility Limitation Status                                       B-26 



  Nativity (See Place of Birth) 



  Noninstitutionalized Group Quarters (See Group Quarters) 



  Occupation (See Industry, Occupation, and Class of Worker) 



  Own Children (See Household Type and Relationship) 



  Per Capita Income (See Income in 1989) 



  Period of Military Service (See Veteran Status) 



  Persons in Family (See Household Type and Relationship) 



  Persons in Households (See Household Type and Relationship) 



  Place of Birth                                                   B-26 



  Place of Work (See Journey to Work) 



  Poverty Status in 1989                                           B-27 



  Presence of Children (See Household Type and Relationship) 



  Private Vehicle Occupancy (See Journey to Work) 



  Race                                                             B-28 



  Reference Week                                                   B-31 



  Related Children (See Household Type and Relationship) 



  Residence in 1985                                                B-32 



  School Enrollment and Labor Force Status                         B-33 



  School Enrollment and Type of School                             B-33 



  Self-Care Limitation Status                                      B-34 



  Sex                                                              B-34 



  Spanish Origin (See Hispanic Origin) 



  Stepfamily (See Household Type and Relationship) 



  Subfamily (See Household Type and Relationship) 



  Time Leaving Home to Go to Work (See Journey to Work) 



  Travel Time to Work (See Journey to Work) 



  Type of School (See School Enrollment and Type of School) 



  Usual Hours Worked Per Week Worked in 1989 (See Work Status in 1989) 



  Veteran Status                                                   B-34 



  Weeks Worked in 1989 (Work Status in 1989) 



  Work Disability Status                                           B-35 



  Work Status in 1989                                              B-35 



  Worker (See Employment Status, see Industry, Occupation, and Class

   of Worker, see Journey to Work, see Work Status in 1989) 



  Workers in Family in 1989 (See Work Status in 1989) 



  Year of Entry                                                    B-36 



  Years of Military Service (See Veteran Status)





HOUSING CHARACTERISTICS                                            B-36 



  Acreage                                                          B-37 



  Age of Structure (See Year Structure Built) 



  Agricultural Sales                                               B-38 



  Bedrooms                                                         B-38 



  Boarded-Up Status                                                B-38 



  Business on Property                                             B-38 



  Condominium Fee                                                  B-39 



  Condominium Status                                               B-39 



  Congregate Housing (See Meals Included in Rent) 



  Contract Rent                                                    B-39 



  Crop Sales (See Agricultural Sales) 



  Duration of Vacancy                                              B-40 



  Farm Residence                                                   B-40 



  Gross Rent                                                       B-40 



  Gross Rent as a Percentage of Household Income in 1989           B-41 



  Homeowner Vacancy Rate (See Vacancy Status)



  House Heating Fuel                                               B-41 



  Housing Units (See Living Quarters) 



  Insurance for Fire, Hazard, and Flood                            B-41 



  Kitchen Facilities                                               B-41 



  Living Quarters                                                  B-36 



  Meals Included in Rent                                           B-41 



  Mobile Home Costs                                                B-42 



  Months Vacant (See Duration of Vacancy) 



  Mortgage Payment                                                 B-42 



  Mortgage Status                                                  B-42 



  Occupied Housing Units (See Living Quarters) 



  Owner-Occupied Housing Units (See Tenure) 



  Persons in Unit                                                  B-43 



  Persons Per Room                                                 B-43 



  Plumbing Facilities                                              B-43 



  Poverty Status of Households in 1989                             B-43 



  Real Estate Taxes                                                B-43 



  Rental Vacancy Rate (See Vacancy Status) 



  Renter-Occupied Housing Units (See Tenure) 



  Rooms                                                            B-44 



  Second or Junior Mortgage Payment                                B-44 



  Selected Monthly Owner Costs                                     B-44 



  Selected Monthly Owner Costs as a Percentage of Household

   Income in 1989                                                  B-45 



  Sewage Disposal                                                  B-45 



  Source of Water                                                  B-45 



  Telephone in Housing Unit                                        B-45 



  Tenure                                                           B-46 



  Type of Structure (See Units in Structure) 



  Units in Structure                                               B-46 



  Usual Home Elsewhere                                             B-47 



  Utilities                                                        B-47 



  Vacancy Status                                                   B-47 



  Vacant Housing Units (See Living Quarters) 



  Value                                                            B-48 



  Vehicles Available                                               B-48 



  Year Householder Moved Into Unit                                 B-49



  Year Structure Built                                             B-49 



DERIVED MEASURES                                                   B-49 



  Interpolation                                                    B-49 



  Mean                                                             B-49 



  Median                                                           B-49 



  Percentages, Rates, and Ratios                                   B-50 



  Quartile                                                         B-50 



POPULATION CHARACTERISTICS 



AGE--The data on age were derived from answers to questionnaire

item 5, which was asked of all persons. The age classification is based

on the age of the person in complete years as of April 1, 1990. The age

response in question 5a was used normally to represent a person's age.

However, when the age response was unacceptable or unavailable, a

person's age was derived from an acceptable year-of-birth response in

question 5b. 



Data on age are used to determine the applicability of other questions

for a person and to classify other characteristics in census

tabulations. Age data are needed to interpret most social and economic

characteristics used to plan and examine many programs and policies.

Therefore, age is tabulated by single years of age and by many

different groupings, such as 5-year age groups. 



Some tabulations are shown by the age of the householder. These data

were derived from the age responses for each householder. (For more

information on householder, see the discussion under "Household Type

and Relationship.") 



Median Age--This measure divides the age distribution into two equal parts:

one-half of the cases falling below the median value and one-half above

the value. Generally, median age is computed on the basis of more

detailed age intervals than are shown in some census publications;

thus, a median based on a less detailed distribution may differ

slightly from a corresponding median for the same population based on a

more detailed distribution. (For more information on medians, see the

discussion under "Derived Measures.") 



Limitation of the Data--Counts in 1970 and 1980 for persons 100 years old

and over were substantially overstated. Improvements were made in the

questionnaire design, in the allocation procedures, and to the respondent

instruction guide to attempt to minimize this problem for the 1990 census.



Review of detailed 1990 census information indicated that respondents

tended to provide their age as of the date of completion of the

questionnaire, not their age as of April 1, 1990. In addition, there

may have been a tendency for respondents to round their age up if they

were close to having a birthday. It is likely that approximately 10

percent of persons in most age groups are actually 1 year younger. For

most single years of age, the misstatements are largely offsetting. The

problem is most pronounced at age 0 because persons lost to age 1 may not

have been fully offset by the inclusion of babies born after April 1, 1990,

and because there may have been more rounding  up to age 1 to avoid

reporting age as 0 years. (Age in complete months was not collected for

infants under age 1.)



The reporting of age 1 year older than age on April 1, 1990, is likely

to have been greater in areas where the census data were collected

later in 1990. The magnitude of this problem was much less in the three

previous censuses where age was typically derived from respondent data

on year of birth and quarter of birth. (For more information on the

design of the age question, see the section below that discusses

"Comparability.") 



Comparability--Age data have been collected in every census. For the first

time since 1950, the 1990 data are not available by quarter year of age.

This change was made so that coded information could be obtained for both

age and year of birth. In each census since 1940, the age of a person

was assigned when it was not reported. In censuses before 1940, with

the exception of 1880, persons of unknown age were shown as a separate

category. Since 1960, assignment of unknown age has been performed by a

general procedure described as "imputation." The specific

procedures for imputing age have been different in each census. (For

more information on imputation, see Appendix C, Accuracy of the Data.) 



ANCESTRY--The data on ancestry were derived from answers to

questionnaire item 13, which was asked of a sample of persons. The

question was based on self-identification; the data on ancestry

represent self-classification by people according to the ancestry

group(s) with which they most closely identify. Ancestry refers to a

person's ethnic origin or descent, "roots," or heritage or the

place of birth of the person or the person's parents or ancestors

before their arrival in the United States. Some ethnic identities, such

as "Egyptian" or "Polish" can be traced to geographic areas

outside the United States, while other ethnicities such as

"Pennsylvania Dutch" or "Cajun" evolved in the United

States. 



The intent of the ancestry question was not to measure the degree of

attachment the respondent had to a particular ethnicity. For example, a

response of "Irish" might reflect total involvement in an "Irish" community

or only a memory of ancestors several generations removed from the

individual.



The Census Bureau coded the responses through an automated review,

edit, and coding operation. The open-ended write-in ancestry item was coded

by subject-matter specialists into a numeric representation using a code

list containing over 1,000 categories. The 1990 code list reflects the

results of the Census Bureau's own research and consultations with many

ethnic experts. Many decisions were made to determine the classification of

responses. These decisions affected the grouping of the tabulated data. For

example, the "Assyrian" category includes both responses of "Assyrian"

and "Chaldean." 



The ancestry question allowed respondents to report one or more

ancestry groups. While a large number of respondents listed a single

ancestry, the majority of answers included more than one ethnic entry.

Generally, only the first two responses reported were coded in 1990. If

a response was in terms of a dual ancestry, for example, Irish-English,

the person was assigned two codes, in this case one for Irish and

another for English. 



However, in certain cases, multiple responses such as "French

Canadian," "Scotch-Irish," "Greek Cypriote," and "Black Dutch" were

assigned a single code reflecting their status as unique groups. If a

person reported one of these unique groups in addition to another group,

for example, "Scotch-Irish English," resulting in three terms, that person

received one code for the unique group ("Scotch-Irish") and another one for

the remaining group ("English"). If a person reported "English Irish

French," only English and Irish were coded. Certain combinations of

ancestries where the ancestry group is a part of another, such as "German-

Bavarian," the responses were coded as a single ancestry using the smaller

group ("Bavarian"). Also, responses such as "Polish-American" or

"Italian-American" were coded and tabulated as a single entry

("Polish" or "Italian"). 



The Census Bureau accepted "American" as a unique ethnicity if it

was given alone, with an ambiguous response, or with State names. If

the respondent listed any other ethnic identity such as "Italian

American," generally the "American" portion of the response

was not coded. However, distinct groups such as "American

Indian," "Mexican American," and "African American" were

coded and identified separately because they represented groups who

considered themselves different from those who reported as

"Indian," "Mexican," or "African," respectively. 



In all tabulations, when respondents provided an unacceptable ethnic

identity (for example, an uncodeable or unintelligible response such as

"multi-national," "adopted," or "I have no idea"), the answer was included

in "Ancestry not reported." 



The tabulations on ancestry are presented using two types of data

presentations--one used total persons as the base, and the other used

total responses as the base. The following are categories shown in the

two data presentations: 



Presentation Based on Persons: 



  Single Ancestries Reported--Includes all persons who reported only one

  ethnic group. Included in this category are persons with multiple-term

  responses such as "Scotch-Irish" who are assigned a single code. 



  Multiple Ancestries Reported--Includes all persons who reported more than

  one group and were assigned two ancestry codes. 



  Ancestry Unclassified--Includes all persons who provided a response that

  could not be assigned an ancestry code because they provided nonsensical

  entries or religious responses. 



Presentations Based on Responses: 



  Total Ancestries Reported--Includes the total number of ancestries

  reported and coded. If a person reported a multiple ancestry such as

  "French Danish," that response was counted twice in the tabulations--once

  in the "French" category and again in the "Danish" category. Thus, the

  sum of the counts in this type of presentation is not the total

  population but the total of all responses. 



  First Ancestry Reported--Includes the first response of all persons who

  reported at least one codeable entry. For example, in this category, the

  count for "Danish" would include all those who reported only Danish and

  those who reported Danish first and then some other group. 



  Second Ancestry Reported--Includes the second response of all persons who

  reported a multiple ancestry. Thus, the count for "Danish" in this

  category includes all persons who reported Danish as the second response,

  regardless of the first response provided. 



The Census Bureau identified hundreds of ethnic groups in the 1990

census. However, it was impossible to show information for every group

in all census tabulations because of space constraints. Publications

such as the 1990 CP-2, Social and Economic Characteristics

and the 1990 CPH-3, Population and Housing Characteristics

for Census Tracts and Block Numbering Areas reports show a limited

number of groups based on the number reported and the advice received

from experts. A more complete distribution of groups is presented in

the 1990 Summary Tape File 4, supplementary reports, and a special

subject report on ancestry. In addition, groups identified specifically

in the questions on race and Hispanic origin (for example, Japanese,

Laotian, Mexican, Cuban, and Spaniard), in general, are not shown

separately in ancestry tabulations. 



Limitation of the Data--Although some experts consider religious

affiliation a component of ethnic identity, the ancestry question was not

designed to collect any information concerning religion. The Bureau of the

Census is prohibited from collecting information on religion. Thus, if a

religion was given as an answer to the ancestry question, it was coded as

an "Other" response. 



Comparability--A question on ancestry was first asked in

the 1980 census. Although there were no comparable data prior to the

1980 census, related information on ethnicity was collected through

questions on parental birthplace, own birthplace, and language which

were included in previous censuses. Unlike other census questions,

there was no imputation for nonresponse to the ancestry question. 



In 1990, respondents were allowed to report more than one ancestry

group; however, only the first two ancestry groups identified were

coded. In 1980, the Census Bureau attempted to code a third ancestry

for selected triple-ancestry responses. 



New categories such as "Arab" and "West Indian" were added to the 1990

question to meet important data needs. The "West Indian" category excluded

"Hispanic" groups such as "Puerto Rican" and "Cuban" that were identified

primarily through the question on Hispanic origin. In 1990, the ancestry

group, "American" is recognized and tabulated as a unique ethnicity. In

1980, "American" was tabulated but included under the category "Ancestry

not specified."



A major improvement in the 1990 census was the use of an automated

coding system for ancestry responses. The automated coding system used

in the 1990 census greatly reduced the potential for error associated

with a clerical review. Specialists with a thorough knowledge of the

subject matter reviewed, edited, coded, and resolved inconsistent or

incomplete responses. 



CITIZENSHIP--The data on citizenship were derived from answers to 

questionnaire item 9, which was asked of a sample of persons. 



Citizen--Persons who indicated that they were native-born and foreign-born

persons who indicated that they have become naturalized. (For more

information on native and foreign born, see the discussion under "Place of

Birth.")



There are four categories of citizenship: (1) born in the United

States, (2) born in Puerto Rico, Guam, the Virgin Islands of the United

States, or the Commonwealth of the Northern Mariana Islands, (3) born

abroad of American parents, and (4) citizen by naturalization. 



Naturalized Citizen--Foreign-born persons who had completed the

naturalization process at the time of the census and upon whom the rights

of citizenship had been conferred.  



Not a Citizen--Foreign-born persons who were not citizens, including

persons who had begun but not completed the naturalization process at the

time of the census. 



Limitation of the Data--Evaluation studies completed after previous

censuses indicated that some persons may have reported themselves as

citizens although they had not yet attained the status. 



Comparability--Similar questions on citizenship were asked in the censuses

of 1820, 1830, 1870, 1890 through 1950, 1970, and 1980. The 1980 question

was asked of a sample of the foreign-born population. In 1990, both native

and foreign-born persons who received the long-form questionnaire were

asked to respond to the citizenship question. 



EDUCATIONAL ATTAINMENT--Data on educational attainment were derived from

answers to questionnaire item 12, which was asked of a sample of persons.

Data are tabulated as attainment for persons 15 years old and over. Persons

are classified according to the highest level of school completed or the

highest degree received. The question included instructions to report the

level of the previous grade attended or the highest degree received for

persons currently enrolled in school. The question included response

categories which allowed persons to report completing the 12th grade

without receiving a high school diploma, and which instructed respondents

to report as "high school graduate(s)"--persons who received either a high

school diploma or the equivalent, for example, passed the Test of General

Educational Development (G.E.D.), and did not attend college. (On the

Military Census Report questionnaire, the lowest response category was

"Less than 9th grade.") 



Instructions included in the 1990 respondent instruction guide, which

was mailed with the census questionnaire, further specified that

schooling completed in foreign or ungraded school systems should be

reported as the equivalent level of schooling in the regular American

system; that vocational certificates or diplomas from vocational,

trade, or business schools or colleges were not to be reported unless

they were college level degrees; and that honorary degrees were not to

be reported. The instructions gave "medicine, dentistry,

chiropractic, optometry, osteopathic medicine, pharmacy, podiatry,

veterinary medicine, law, and theology" as examples of professional

school degrees, and specifically excluded "barber school,

cosmetology, or other training for a specific trade" from the

professional school category. The order in which they were listed

suggested that doctorate degrees were "higher" than professional

school degrees, which were "higher" than master's degrees. 



Persons who did not report educational attainment were assigned the

attainment of a person of the same age, race or Spanish origin, and sex

who resided in the same or a nearby area. Persons who filled more than

one circle were edited to the highest level or degree reported. 



High School Graduate or Higher--Includes persons whose highest degree was a

high school diploma or its equivalent, persons who attended college or

professional school, and persons who received a college, university, or

professional degree. Persons who reported completing the 12th grade but not

receiving a diploma are not included.



Not Enrolled, Not High School Graduate--Includes persons of compulsory

school attendance age or above who were not enrolled in school and were not

high school graduates; these persons may be taken to be "high school

dropouts." There is no restriction on when they "dropped out" of school,

and they may have never attended high school. 



In prior censuses, "Median school years completed" was used as

a summary measure of educational attainment. In 1990, the median can

only be calculated for groups of which less than half the members have

attended college. "Percent high school graduate or higher" and

"Percent bachelor's degree or higher" are summary measures which

can be calculated from the present data and offer quite readily

interpretable measures of differences between population subgroups. To

make comparisons over time, "Percent high school graduate or

higher" can be calculated and "Percent bachelor's degree or

higher" can be approximated with data from previous censuses. 



Comparability--From 1840 to 1930, the census measured educational

attainment by means of a basic literacy question. In 1940, a single

question was asked on highest grade of school completed. In the censuses of

1950 through 1980, a two-part question asking highest grade of school

attended and whether that grade was finished was used to construct highest

grade or year of school completed. For persons who have not attended

college, the response categories in the 1990 educational attainment

question should produce data which are comparable to data on highest grade

completed from earlier censuses. 



The response categories for persons who have attended college were

modified from earlier censuses because there was some ambiguity in

interpreting responses in terms of the number of years of college

completed. For instance, it was not clear whether "completed the

fourth year of college," "completed the senior year of

college," and "college graduate" were synonymous. Research

conducted shortly before the census suggests that these terms were more

distinct in 1990 than in earlier decades, and this change may have

threatened the ability to estimate the number of "college

graduates" from the number of persons reported as having completed

the fourth or a higher year of college. It was even more difficult to

make inferences about post-baccalaureate degrees and "Associate"

degrees from highest year of college completed. Thus, comparisons of

post-secondary educational attainment in this and earlier censuses

should be made with great caution. 



In the 1960 and subsequent censuses, persons for whom educational

attainment was not reported were assigned the same attainment level as

a similar person whose residence was in the same or a nearby area. In

the 1940 and 1950 censuses, persons for whom educational attainment was

not reported were not allocated. 



EMPLOYMENT STATUS--The data on employment status were derived from answers

to questionnaire items 21, 25, and 26, which were asked of a sample of

persons. The series of questions on employment status was asked of all

persons 15 years old and over and was designed to identify, in this

sequence: (1) persons who worked at any time during the reference week; (2)

persons who did not work during the reference week but who had jobs or

businesses from which they were temporarily absent (excluding layoff); (3)

persons on layoff; and (4) persons who did not work during the reference

week, but who were looking for work during the last four weeks and were

available for work during the reference week. (For more information, see

the discussion under "Reference Week.") 



The employment status data shown in this and other 1990 census

tabulations relate to persons 16 years old and over. Some tabulations

showing employment status, however, include persons 15 years old. By

definition, these persons are classified as "Not in Labor

Force.". In the 1940, 1950, and 1960 censuses, employment status

data were presented for persons 14 years old and over. The change in

the universe was made in 1970 to agree with the official measurement of

the labor force as revised in January 1967 by the U.S. Department of

Labor. The 1970 census was the last to show employment data for persons

14 and 15 years old. 



Employed--All civilians 16 years old and over who were either (1) "at

work"--those who did any work at all during the reference week as

paid employees, worked in their own business or profession, worked on

their own farm, or worked 15 hours or more as unpaid workers on a

family farm or in a family business; or (2) were "with a job but not

at work"--those who did not work during the reference week but had

jobs or businesses from which they were temporarily absent due to

illness, bad weather, industrial dispute, vacation, or other personal

reasons. Excluded from the employed are persons whose only activity

consisted of work around the house or unpaid volunteer work for

religious, charitable, and similar organizations; also excluded are

persons on active duty in the United States Armed Forces. 



Unemployed--All civilians 16 years old and over are classified as

unemployed if they (1) were neither "at work" nor "with a job but not at

work" during the reference week, and (2) were looking for work

during the last 4 weeks, and (3) were available to accept a job. Also

included as unemployed are civilians who did not work at all during the

reference week and were waiting to be called back to a job from which

they had been laid off. Examples of job seeking activities are: 



   Registering at a public or private employment office 



   Meeting with prospective employers 



   Investigating possibilities for starting a professional

   practice or opening a business



   Placing or answering advertisements 



   Writing letters of application 



   Being on a union or professional register



Civilian Labor Force--Consists of persons classified as employed or

unemployed in accordance with the criteria described above. 



Experienced Unemployed--These are unemployed persons who have worked at any

time in the past. 



Experienced Civilian Labor Force--Consists of the employed and the

experienced unemployed. 



Labor Force--All persons classified in the civilian labor force plus

members of the U.S. Armed Forces (persons on active duty with the United

States Army, Air Force, Navy, Marine Corps, or Coast Guard). 



Not in Labor Force--All persons 16 years old and over who are not

classified as members of the labor force. This category consists mainly of

students, housewives, retired workers, seasonal workers enumerated in an

off season who were not looking for work, institutionalized persons, and

persons doing only incidental unpaid family work (less than 15 hours

during the reference week). 



Worker--This term appears in connection with several subjects: journey-to-

work items, class of worker, weeks worked in 1989, and number of workers in

family in 1989. Its meaning varies and, therefore, should be determined

in each case by referring to the definition of the subject in which it

appears. 



Actual Hours Worked Last Week--All persons who reported working during the

reference week were asked to report in questionnaire item 21b the number of

hours that they worked. The statistics on hours worked pertain to the

number of hours actually worked at all jobs, and do not necessarily reflect

the number of hours typically or usually worked or the scheduled number of

hours.  The concept of "actual hours" differs from that of "usual

hours" described below. The number of persons who worked only a

small number of hours is probably understated since such persons

sometimes consider themselves as not working. Respondents were asked to

include overtime or extra hours worked, but to exclude lunch hours,

sick leave, and vacation leave. 



Limitation of the Data--The census may understate the number of employed

persons because persons who have irregular, casual, or unstructured jobs

sometimes report themselves as not working. The number of employed persons

"at work" is probably overstated in the census (and conversely, the

number of employed "with a job, but not at work" is understated)

since some persons on vacation or sick leave erroneously reported

themselves as working. This problem has no effect on the total number

of employed persons. The reference week for the employment data is not

the same for all persons. Since persons can change their employment

status from one week to another, the lack of a uniform reference week

may mean that the employment data do not reflect the reality of the

employment situation of any given week. (For more information, see the

discussion under "Reference Week.") 



Comparability--The questionnaire items and employment status concepts for

the 1990 census are essentially the same as those used in the 1980 and 1970

censuses. However, these concepts differ in many respects from those

associated with the 1950 and 1960 censuses. 



Since employment data from the census are obtained from respondents in

households, they differ from statistics based on reports from

individual business establishments, farm enterprises, and certain

government programs. Persons employed at more than one job are counted

only once in the census and are classified according to the job at

which they worked the greatest number of hours during the reference

week. In statistics based on reports from business and farm

establishments, persons who work for more than one establishment may be

counted more than once. Moreover, some tabulations may exclude private

household workers, unpaid family workers, and self-employed persons,

but may include workers less than 16 years of age. 



An additional difference in the data arises from the fact that persons

who had a job but were not at work are included with the employed in

the census statistics, whereas many of these persons are likely to be

excluded from employment figures based on establishment payroll

reports. Furthermore, the employment status data in census tabulations

include persons on the basis of place of residence regardless of where

they work, whereas establishment data report persons at their place of

work regardless of where they live. This latter consideration is

particularly significant when comparing data for workers who commute

between areas.



Census data on actual hours worked during the reference week may differ

from data from other sources. The census measures hours actually

worked, whereas some surveys measure hours paid for by employers.

Comparability of census actual hours worked data may also be affected

by the nature of the reference week (see "Reference Week"). 



For several reasons, the unemployment figures of the Census Bureau are

not comparable with published figures on unemployment compensation

claims. For example, figures on unemployment compensation claims

exclude persons who have exhausted their benefit rights, new workers

who have not earned rights to unemployment insurance, and persons

losing jobs not covered by unemployment insurance systems (including

some workers in agriculture, domestic services, and religious

organizations, and self-employed and unpaid family workers). In

addition, the qualifications for drawing unemployment compensation

differ from the definition of unemployment used by the Census Bureau.

Persons working only a few hours during the week and persons with a job

but not at work are sometimes eligible for unemployment compensation

but are classified as "Employed" in the census. Differences in

the geographical distribution of unemployment data arise because the

place where claims are filed may not necessarily be the same as the

place of residence of the unemployed worker. 



The figures on employment status from the decennial census are

generally comparable with similar data collected in the Current

Population Survey. However, some difference may exist because of

variations in enumeration and processing techniques. 



FERTILITY--The data on fertility (also referred to as "children ever born")

were derived from answers to questionnaire item 20, which was asked of a

sample of women 15 years old and over regardless of marital status.

Stillbirths, stepchildren, and adopted children were excluded from the

number of children ever born. Ever-married women were instructed to include

all children born to them before and during their most recent marriage,

children no longer living, and children away from home, as well as children

who were still living in the home.  Never-married women were instructed to

include all children born to them. 



Data are most frequently presented in terms of the aggregate number of

children ever born to women in the specified category and in terms of

the rate per 1,000 women. For purposes of calculating the aggregate,

the open-ended response category, "12 or more" is assigned a value of 13. 



Limitation of the Data--Although the data are assumed to be less complete

for out-of-wedlock births than for births occurring within marriage,

comparisons of 1980 census data on the fertility of single women with other

census sources and administrative records indicate that no significant

differences were found between different data sources; that is, 1980 census

data on children ever born to single women were complete with no

significant understatements of childbearing. 



Comparability--The wording of the question on children ever born was the

same in 1990 as in 1980. In 1970, however, the question on children ever

born was asked of all ever-married women but only of never-married women

who received self-administered questionnaires. Therefore, rates and numbers

of children ever born to single women in 1970 may be understated. Data

presented for children ever born to ever-married women are comparable

for the 1990 census and all previous censuses containing this question.



GROUP QUARTERS--All persons not living in households are classified by the

Census Bureau as living in group quarters. Two general categories of

persons in group quarters are recognized:



  (1) institutionalized persons and 

  (2) other persons in group quarters (also referred to as

      "noninstitutional group quarters"). 



Institutionalized Persons--Includes persons under formally authorized,

supervised care or custody in institutions at the time of enumeration. Such

persons are classified as "patients or inmates" of an institution

regardless of the availability of nursing or medical care, the length of

stay, or the number of persons in the institution. Generally,

institutionalized persons are restricted to the institutional buildings and

grounds (or must have passes or escorts to leave) and thus have limited

interaction with the surrounding community. Also, they are generally under

the care of trained staff who have responsibility for their safekeeping and

supervision.  



Type of Institution--The type of institution was determined as part of

census enumeration activities. For institutions which specialize in only

one specific type of service, all patients or inmates were given the same

classification.  For institutions which had multiple types of major

services (usually general hospitals and Veterans' Administration

hospitals), patients were classified according to selected types of wards.

For example, in psychiatric wards of hospitals, patients were classified in

"mental (psychiatric) hospitals"; in hospital wards for persons with

chronic diseases, patients were classified in "hospitals for the

chronically ill." Each patient or inmate was classified in only one type of

institution. Institutions include the following types: 



   Correctional Institutions--Includes prisons, Federal

   detention centers, military stockades and jails, police lockups,

   halfway houses, local jails, and other confinement facilities,

   including work farms. 



   Prisons--Where persons convicted of crimes serve their

   sentences. In some census products, the prisons are classified by two

   types of control:



     (1) "Federal" (operated by the Bureau of  Prisons of the Department

     of Justice) and (2) "State." Residents who are criminally insane were

     classified on the basis of where they resided at the time of

     enumeration: (1) in institutions (or hospital wards) operated by

     departments of correction or similar agencies; or



     (2) in institutions operated by departments of mental health or

     similar agencies. 



   Federal Detention Centers--Operated by the Immigration

   and Naturalization Service (INS) and the Bureau of Prisons. These

   facilities include detention centers used by the Park Police; Bureau of

   Indian Affairs Detention Centers; INS Centers, such as the INS Federal

   Alien Detention Facility; INS Processing Centers; and INS Contract

   Detention Centers used to detain aliens under exclusion or deportation

   proceedings, as well as those aliens who have not been placed into

   proceedings, such as custodial required departures; and INS Detention

   Centers operated within local jails, and State and Federal prisons. 



   Military Stockades, Jails--Operated by military police

   and used to hold persons awaiting trial or convicted of violating

   military laws. 



   Local Jails and Other Confinement Facilities--Includes

   facilities operated by counties and cities that primarily hold persons

   beyond arraignment, usually for more than 48 hours. Also included in

   this category are work farms used to hold persons awaiting trial or

   serving time on relatively short sentences and jails run by private

   businesses under contract for local governments (but not by

   State governments). 



   Police Lockups--Temporary-holding facilities operated

   by county and city police that hold persons for 48 hours or less only

   if they have not been formally charged in court. 



   Halfway Houses--Operated for correctional purposes and include

   probation and restitution centers, pre- release centers, and

   community-residential centers. 



   Other Types of Correctional Institutions--Privately

   operated correctional facilities and correctional facilities

   specifically for alcohol/drug abuse. 



Nursing Homes--Comprises a heterogeneous group of places. The majority

of patients are elderly, although persons who require nursing care

because of chronic physical conditions may be found in these homes

regardless of their age. Included in this category are skilled-nursing

facilities, intermediate-care facilities, long-term care rooms in wards

or buildings on the grounds of hospitals, or long-term care

rooms/nursing wings in congregate housing facilities.

Also included are nursing, convalescent, and rest homes, such as

soldiers', sailors', veterans', and fraternal or religious homes for

the aged, with or without nursing care. In some census products,

nursing homes are classified by type of ownership as "Federal,"

"State," "Private not-for-profit," and "Private for

profit." 



Mental (Psychiatric) Hospitals--Includes hospitals or

wards for the criminally insane not operated by a prison, and

psychiatric wards of general hospitals and veterans' hospitals.

Patients receive supervised medical/nursing care from formally-trained

staff. In some census products, mental hospitals are classified by type

of ownership as "Federal," "State or local,"

"Private," and "Ownership not known." 



Hospitals for Chronically Ill--Includes hospitals for

patients who require long-term care, including those in military

hospitals and wards for the chronically ill located on military bases;

or other hospitals or wards for the chronically ill, which include

tuberculosis hospitals or wards, wards in general and Veterans'

Administration hospitals for the chronically ill, neurological wards,

hospices, wards for patients with Hansen's Disease (leprosy) and other

incurable diseases, and other unspecified wards for the chronically

ill. Patients who had no usual home elsewhere were enumerated as part

of the institutional population in the wards of general and military

hospitals. Most hospital patients are at the hospital temporarily and

were enumerated at their usual place of residence. (For more

information, see "Wards in General and Military Hospitals for

Patients Who Have No Usual Home Elsewhere.") 



Schools, Hospitals, or Wards for the Mentally Retarded--Includes those

institutions such as wards in hospitals for the mentally retarded, and

intermediate-care facilities for the mentally retarded that provide

supervised medical/nursing care from formally-trained staff. In some

census products, this category is classified by type of ownership as

"Federal," "State or local," "Private," and "Ownership not known." 



Schools, Hospitals, or Wards for the Physically Handicapped--Includes

three types of institutions: institutions for the blind, those for the

deaf, and orthopedic wards and institutions for the physically

handicapped. Institutions for persons with speech problems are

classified with "institutions for the deaf." The category "orthopedic

wards and institutions for the physically handicapped" includes those

institutions providing relatively long-term care to accident victims,

and to persons with polio, cerebral palsy, and muscular dystrophy. In

some census products, this category is classified by type of ownership

as "Public," "Private," and "Ownership not known." 



Hospitals, and Wards for Drug/Alcohol Abuse--Includes hospitals, and

hospital wards in psychiatric and general hospitals.  These facilities

are equipped medically and designed for the diagnosis and treatment of

medical or psychiatric illnesses associated with alcohol or drug abuse.

Patients receive supervised medical care from formally-trained staff. 



Wards in General and Military Hospitals for Patients Who

Have No Usual Home Elsewhere--Includes maternity, neonatal,

pediatric (including wards for boarder babies), military, and surgical

wards of hospitals, and wards for persons with infectious diseases. 



Juvenile Institutions--Includes homes, schools, and other institutions

providing care for children (short- or long-term care). Juvenile

institutions include the following types: 



   Homes for Abused, Dependent, and Neglected Children--Includes

   orphanages and other institutions which provide long-term care

   (usually more than 30 days) for children. This category

   is classified in some census products by type of ownership as

   "Public" and "Private." 



   Residential Treatment Centers--Includes those institutions which

   primarily serve children who, by clinical diagnosis, are moderately

   or seriously disturbed emotionally. Also, these institutions provide

   long-term treatment services, usually supervised or directed by a

   psychiatrist. 



   Training Schools for Juvenile Delinquents--Includes residential

   training schools or homes, and industrial schools, camps, or farms for

   juvenile delinquents. 



   Public Training Schools for Juvenile Delinquents--Usually operated by

   a State agency (for example, department of welfare, corrections, or a

   youth authority). Some are operated by county and city governments.

   These public training schools are specialized institutions serving

   delinquent children, generally between the ages of 10 and 17 years

   old, all of whom are committed by the courts. 



   Private Training Schools--Operated under private auspices. Some of the

   children they serve are committed by the courts as delinquents. Others

   are referred by parents or social agencies because of delinquent

   behavior. One difference between private and public training schools

   is that, by their administrative policy, private schools have control

   over their selection and intake. 



Detention Centers--Includes institutions providing short-term care (usually

30 days or less) primarily for delinquent children pending disposition of

their cases by a court. This category also covers diagnostic centers. In

practice, such institutions may be caring for both delinquent and neglected

children pending court disposition.  



Other Persons in Group Quarters (also referred to as "noninstitutional

group quarters")--Includes all persons who live in group quarters other

than institutions. Persons who live in the following living quarters are

classified as "other persons in group quarters" when there are 10

or more unrelated persons living in the unit; otherwise, these living

quarters are classified as housing units. 



Rooming Houses--Includes persons residing in rooming and boarding houses

and living in quarters with 10 or more unrelated persons. 



Group Homes--Includes "community-based homes" that provide care and

supportive services. Such places include homes for the mentally ill,

mentally retarded, and physically handicapped; drug/alcohol halfway houses;

communes; and maternity homes for unwed mothers. 



Homes for the Mentally Ill--Includes community-based homes that provide

care primarily for the mentally ill. In some data products, this category

is classified by type of ownership as "Federal," "State," "Private," and

"Ownership not known." Homes which combine treatment of the physically

handicapped with treatment of the mentally ill are counted as homes for the

mentally ill. 



Homes for the Mentally Retarded--Includes community-based homes that

provide care primarily for the mentally retarded. Homes which combine

treatment of the physically handicapped with treatment of the mentally

retarded are counted as homes for the mentally retarded.  This category is

classified by type of ownership in some census products, as "Federal,"

"State," "Private," or "Ownership not known." 



Homes for the Physically Handicapped--Includes community-based homes for

the blind, for the deaf, and other community-based homes for the physically

handicapped. Persons with speech problems are classified with homes for the

deaf. In some census products, this category is classified by type of

ownership as "Public," "Private," or "Ownership not known." 



Homes or Halfway Houses for Drug/Alcohol Abuse--Includes persons with no

usual home elsewhere in places that provide community-based care and

supportive services to persons suffering from a drug/alcohol addiction and

to recovering alcoholics and drug abusers. Places providing community-based

care for drug and alcohol abusers include group homes, detoxification

centers, quarterway houses (residential treatment facilities that work

closely with accredited hospitals), halfway houses, and recovery homes for

ambulatory, mentally competent recovering alcoholics and drug abusers

who may be re-entering the work force. 



Maternity Homes for Unwed Mothers--Includes persons with no usual home

elsewhere in places that provide domestic care for unwed mothers and their

children. These homes may provide social services and post-natal care

within the facility, or may make arrangements for women to receive such

services in the community.  Nursing services are usually available in the

facility.  



Other Group Homes--Includes persons with no usual home elsewhere in

communes, foster care homes, and job corps centers with 10 or more

unrelated persons. These types of places provide communal living quarters,

generally for persons who have formed their own community in which they

have common interests and often share or own property jointly. 



Religious Group Quarters--Includes, primarily, group quarters for nuns

teaching in parochial schools and for priests living in rectories. It also

includes other convents and monasteries, except those associated with a

general hospital or an institution.  



College Quarters Off Campus--Includes privately-owned rooming and boarding

houses off campus, if the place is reserved exclusively for occupancy by

college students and if there are 10 or more unrelated persons. In census

products, persons in this category are classified as living in a college

dormitory. 



Persons residing in certain other types of living arrangements are

classified as living in "noninstitutional group quarters" regardless of the

number of people sharing the unit. These include persons residing in the

following types of group quarters: 



   College Dormitories--Includes college students in

   dormitories (provided the dormitory is restricted to students who do

   not have their families living with them), fraternity and sorority

   houses, and on-campus residential quarters used exclusively for those

   in religious orders who are attending college. Students in

   privately-owned rooming and boarding houses off campus are also

   included, if the place is reserved exclusively for occupancy by

   college-level students and if there are 10 or more unrelated persons. 



   Military Quarters--Includes military personnel living

   in barracks and dormitories on base, in transient quarters on base for

   temporary residents (both civilian and military), and on military

   ships. However, patients in military hospitals receiving treatment for

   chronic diseases or who had no usual home elsewhere, and persons being

   held in military stockades were included as part of the institutional

   population. 



   Agriculture Workers' Dormitories--Includes persons in

   migratory farm workers' camps on farms, bunkhouses for ranch hands, and

   other dormitories on farms, such as those on "tree farms." 



   Other Workers' Dormitories--Includes persons in logging

   camps, construction workers' camps, firehouse dormitories, job-training

   camps, energy enclaves (Alaska only), and nonfarm migratory workers'

   camps (for example, workers in mineral and mining camps). 



   Emergency Shelters for Homeless Persons (with sleeping

   facilities) and Visible in Street Locations--Includes persons

   enumerated during the "Shelter-and-Street-Night" operation primarily on

   March 20-21, 1990. Enumerators were instructed not to ask if a person

   was "homeless." If a person was at one of the locations below on March

   20-21, the person was counted as described below. (For more information

   on the "Shelter-and-Street-Night" operation, see Appendix D, Collection

   and Processing Procedures.) This category is divided into four

   classifications: 



     Emergency Shelters for Homeless Persons (with sleeping

     facilities)--Includes persons who stayed overnight on March 20,

     1990, in permanent and temporary emergency housing, missions,

     hotels/motels, and flophouses charging $12 or less (excluding taxes)

     per night; Salvation Army shelters, hotels, and motels used

     entirely for homeless persons regardless of the nightly rate

     charged; rooms in hotels and motels used partially for the

     homeless; and similar places known to have persons who have no usual

     home elsewhere staying overnight. If not shown separately, shelters

     and group homes that provide temporary sleeping facilities for

     runaway, neglected, and homeless children are included in this  

     category in data products. 



     Shelters for Runaway, Neglected, and Homeless Children--Includes

     shelters/group homes which provide temporary sleeping facilities for

     juveniles.  



Visible in Street Locations--Includes street blocks and open public

locations designated before March 20, 1990, by city and community officials

as places where the homeless congregate at night. All persons found at

predesignated street sites from 2 a.m. to 4 a.m. and leaving abandoned or

boarded-up buildings from 4 a.m. to 8 a.m. on March 21, 1990, were

enumerated during "street" enumeration, except persons in uniform such as

police and persons engaged in obvious money-making activities other than

begging or panhandling. Enumerators were instructed not to ask if a

person was "homeless." 



This cannot be considered a complete count of all persons living on the

streets because those who were so well hidden that local people did not

know where to find them were likely to have been missed as were persons

moving about or in places not identified by local officials. It is also

possible that persons with homes could have been included in the count

of "visible in street locations" if they were present when the

enumerator did the enumeration of a particular block. 



Predesignated street sites include street corners, parks, bridges,

persons emerging from abandoned and boarded-up buildings, noncommercial

campsites (tent cities), all-night movie theaters, all-night

restaurants, emergency hospital waiting rooms, train stations,

airports, bus depots, and subway stations. 



Shelters for Abused Women (Shelters Against Domestic Violence or Family

Crisis Centers)--Includes community-based homes or shelters that provide

domiciliary care for women who have sought shelter from family violence and

who may have been physically abused. Most shelters also provide care for

children of abused women.  These shelters may provide social services,

meals, psychiatric treatment, and counseling. In some census products,

"shelters for abused women" are included in the category "other

noninstitutional group quarters." 



Dormitories for Nurses and Interns in General and Military

Hospitals--Includes group quarters for nurses and other staff

members. It excludes patients. 



Crews of Maritime Vessels--Includes officers, crew members, and passengers

of maritime U.S. flag vessels. All ocean-going and Great Lakes ships are

included.  



Staff Residents of Institutions--Includes staff residing in group quarters

on institutional grounds who provide formally-authorized, supervised care

or custody for the institutionalized population. 



Other Nonhousehold Living Situations--Includes persons with no usual home

elsewhere enumerated during transient or "T-Night" enumeration at YMCA's,

YWCA's, youth hostels, commercial and government-run campgrounds,

campgrounds at racetracks, fairs, and carnivals, and similar transient

sites. 



Living Quarters for Victims of Natural Disasters--Includes living quarters

for persons temporarily displaced by natural disasters. 



Limitation of the Data--Two types of errors can occur in the classification

of "types of group quarters": 



   Misclassification of Group Quarters--During the 1990 Special Place

   Prelist operation, the enumerator determined the type of group quarters

   associated with each special place in their assignment.  The enumerator

   used the Alphabetical Group Quarters Code List and Index to the

   Alphabetical Group Quarters Code List to assign a two-digit code

   number followed by either an "I," for institutional, or an

   "N," for noninstitutional to each group quarters. In 1990,

   unacceptable group quarter codes were edited. (For more information on

   editing of unacceptable data, see Appendix C, Accuracy of the Data.)



   No Classification (unknowns)--The imputation rate for type of

   institution was higher in 1980 (23.5 percent) than in 1970 (3.3

   percent). Improvements were made to the 1990 Alphabetical Group

   Quarters Code List; that is, the inclusion of more group quarters

   categories and an "Index to the Alphabetical Group Quarters Code

   List." (For more information on the allocation rates for Type of

   Institution, see the allocation rates in 1990 CP-1, General

   Population Characteristics.) 



In previous censuses, allocation rates for demographic characteristics

(such as age, sex, race, and marital status) of the institutional

population were similar to those for the total population. The allocation

rates for sample characteristics such as school enrollment, highest grade

completed, income, and veteran status for the institutional and

noninstitutional group quarters population have been substantially higher

than the population in households at least as far back as the 1960 census.

The data, however, have historically presented a reasonable picture of the

institutional and noninstitutional group quarters population. 



Shelter and Street Night (S-Night)--For the 1990 census "Shelter-and-

Street-Night" operation, persons well hidden, moving about, or in locations

enumerators did not visit were likely to be missed. The number of people

missed will never be known; thus, the 1990 census cannot be considered to

include a definitive count of America's total homeless population. It does,

however, give an idea of relative differences among areas of the country.

Other components were counted as part of regular census procedures. 



The count of persons in shelters and visible on the street could have

been affected by many factors. How much the factors affected the count

can never be answered definitively, but some elements include:



How well enumerators were trained and how well they followed

procedures.



How well the list of shelter and street locations given to the

Census Bureau by the local government reflected the actual places that

homeless persons stay at night.



Cities were encouraged to open temporary shelters for census night,

and many did that and actively encouraged people to enter the shelters.

Thus, people who may have been on the street otherwise were in shelters

the night of March 20, so that the ratio of shelter-to-street

population could be different than usual.



The weather, which was unusually cold in some parts of the country,

could affect how likely people were to seek emergency shelter or to be

more hidden than usual if they stayed outdoors.



The media occasionally interfered with the ability to do the count.



How homeless people perceived the census and whether they wanted to

be counted or feared the census and hid from it.



The Census Bureau conducted two assessments of Shelter and Street

Night: (1) the quality of the lists of shelters used for the

Shelter-and-Street-Night operation, and (2) how well procedures were

followed by census- takers for the street count in parts of five cities

(Chicago, Los Angeles, New Orleans, New York, and Phoenix). Information

about these two assessments is available from the Chief, Center for

Survey Methods Research, Bureau of the Census, Washington, DC 20233.



Comparability--For the 1990 census, the definition of institutionalized

persons was revised so that the definition of "care" only includes persons

under organized medical or formally-authorized, supervised care or

custody. As a result of this change to the institutional definition,

maternity homes are classified as noninstitutional rather than

institutional group quarters as in previous censuses. The following

types of other group quarters are classified as institutional rather

than noninstitutional group quarters: "halfway houses (operated for

correctional purposes)" and "wards in general and military

hospitals for patients who have no usual home elsewhere," which

includes maternity, neonatal, pediatric, military, and surgical wards

of hospitals, other-purpose wards of hospitals, and wards for

infectious diseases. These changes should not significantly affect the

comparability of data with earlier censuses because of the relatively

small number of persons involved. 



As in 1980, 10 or more unrelated persons living together were

classified as living in noninstitutional group quarters. In 1970, the

criteria was six or more unrelated persons. 



Several changes also have occurred in the identification of specific

types of group quarters. For the first time, the 1990 census identifies

separately the following types of correctional institutions: persons in

halfway houses (operated for correctional purposes), military stockades

and jails, and police lockups. In 1990, tuberculosis hospitals or wards

are included with hospitals for the chronically ill; in 1980, they were

shown separately. For 1990, the noninstitutional group quarters

category, "Group homes" is further classified as: group homes for

drug/alcohol abuse; maternity homes (for unwed mothers), group homes

for the mentally ill, group homes for the mentally retarded, and group

homes for the physically handicapped. Persons living in communes,

foster-care homes, and job corps centers are classified with "Other

group homes" only if 10 or more unrelated persons share the unit;

otherwise, they are classified as housing units. 



In 1990, workers' dormitories were classified as group quarters

regardless of the number of persons sharing the dorm. In 1980, 10 or

more unrelated persons had to share the dorm for it to be classified as

a group quarters. In 1960, data on persons in military barracks were

shown only for men. In subsequent censuses, they include both men and

women. 



In 1990 census data products, the phrase "inmates of institutions" was

changed to "institutionalized persons." Also, persons living in

noninstitutional group quarters were referred to as "other persons in group

quarters," and the phrase "staff residents" was used for staff living in

institutions.



In 1990, there are additional institutional categories and noninstitutional

group quarters categories compared with the 1980 census. The institutional

categories added include "hospitals and wards for drug/alcohol abuse" and

"military hospitals for the chronically ill." The noninstitutional group

quarters categories added include emergency shelters for homeless persons;

shelters for runaway, neglected, and homeless children; shelters for abused

women; and visible-in-street locations. Each of these noninstitutional

group quarters categories was enumerated on March 20-21, 1990, during the

"Shelter-and-Street-Night" operation. (For more information on

the "Shelter-and-Street-Night" operation, see Appendix D, Collection and

Processing Procedures.) 



HISPANIC ORIGIN--The data on Spanish/Hispanic origin were derived from

answers to questionnaire item 7, which was asked of all persons. Persons of

Hispanic origin are those who classified themselves in one of the

specific Hispanic origin categories listed on the questionnaire--"Mexican,"

"Puerto Rican," or "Cuban"--as well as those who indicated that they were

of "other Spanish/Hispanic" origin. Persons of "Other Spanish/Hispanic"

origin are those whose origins are from Spain, the Spanish-speaking

countries of Central or South America, or the Dominican Republic, or they

are persons of Hispanic origin identifying themselves generally as Spanish,

Spanish-American, Hispanic, Hispano, Latino, and so on. Write-in responses

to the "other Spanish/Hispanic" category were coded only for sample data. 



Origin can be viewed as the ancestry, nationality group, lineage, or

country of birth of the person or the person's parents or ancestors

before their arrival in the United States. Persons of Hispanic origin

may be of any race. 



Some tabulations are shown by the Hispanic origin of the householder.

In all cases where households, families, or occupied housing units are

classified by Hispanic origin, the Hispanic origin of the householder

is used. (See the discussion of householder under "Household Type

and Relationship.") 



During direct interviews conducted by enumerators, if a person could

not provide a single origin response, he or she was asked to select,

based on self-identification, the group which best described his or her

origin or descent. If a person could not provide a single group, the

origin of the person's mother was used. If a single group could not be

provided for the person's mother, the first origin reported by the

person was used. 



If any household member failed to respond to the Spanish/Hispanic

origin question, a response was assigned by the computer according to

the reported entries of other household members by using specific rules

of precedence of household relationship. In the processing of sample

questionnaires, responses to other questions on the questionnaire, such

as ancestry and place of birth, were used to assign an origin before

any reference was made to the origin reported by other household

members. If an origin was not entered for any household member, an

origin was assigned from another household according to the race of the

householder. This procedure is a variation of the general imputation

process described in Appendix C, Accuracy of the Data. 



Comparability--There may be differences between the total Hispanic origin

population based on 100-percent tabulations and sample tabulations. Such

differences are the result of sampling variability, nonsampling error,

and more extensive edit procedures for the Spanish/Hispanic origin item

on the sample questionnaires. (For more information on sampling

variability and nonsampling error, see Appendix C, Accuracy of the

Data.) 



The 1990 data on Hispanic origin are generally comparable with those

for the 1980 census. However, there are some differences in the format

of the Hispanic origin question between the two censuses. For 1990, the

word "descent" was deleted from the 1980 wording. In addition,

the term "Mexican-Amer." used in 1980 was shortened further to

"Mexican-Am." to reduce misreporting (of "American") in

this category detected in the 1980 census. Finally, the 1990 question

allowed those who reported as "other Spanish/Hispanic" to write

in their specific Hispanic origin group. 



Misreporting in the "Mexican-Amer." category of the 1980 census

item on Spanish/Hispanic origin may affect the comparability of 1980

and 1990 census data for persons of Hispanic origin for certain areas

of the country. An evaluation of the 1980 census item on

Spanish/Hispanic origin indicated that there was misreporting in the

Mexican origin category by White and Black persons in certain areas.

The study results showed evidence that the misreporting occurred in the

South (excluding Texas), the Northeast (excluding the New York City

area), and a few States in the Midwest Region. Also, results based on

available data suggest that the impact of possible misreporting of

Mexican origin in the 1980 census was severe in those portions of the

above-mentioned regions where the Hispanic origin population was

generally sparse. However, national 1980 census data on the Mexican

origin population or total Hispanic origin population at the national

level was not seriously affected by the reporting problem. (For a more

detailed discussion of the evaluation of the 1980 census

Spanish/Hispanic origin item, see the 1980 census Supplementary

Reports.) 



The 1990 and 1980 census data on the Hispanic population are not

directly comparable with 1970 Spanish origin data because of a number

of factors: (1) overall improvements in the 1980 and 1990 censuses, (2)

better coverage of the population, (3) improved question designs, and

(4) an effective public relations campaign by the Census Bureau with

the assistance of national and community ethnic groups. 



Specific changes in question design between the 1980 and 1970 censuses

included the placement of the category "No, not Spanish/Hispanic"

as the first category in that question. (The corresponding category

appeared last in the 1970 question.) Also, the 1970 category

"Central or South American" was deleted because in 1970 some

respondents misinterpreted the category; furthermore, the designations

"Mexican-American" and "Chicano" were added to the Spanish/Hispanic origin

question in 1980. In the 1970 census, the question on Spanish origin was

asked of only a 5-percent sample of the population. 



HOUSEHOLD TYPE AND RELATIONSHIP



Household--A household includes all the persons who occupy a housing unit.

A housing unit is a house, an apartment, a mobile home, a group of rooms,

or a single room that is occupied (or if vacant, is intended for occupancy)

as separate living quarters. Separate living quarters are those in which

the occupants live and eat separately from any other persons in the

building and which have direct access from the outside of the building or

through a common hall. The occupants may be a single family, one person

living alone, two or more families living together, or any other group of

related or unrelated persons who share living arrangements. 



In 100-percent tabulations, the count of households or householders

always equals the count of occupied housing units. In sample tabulations,

the numbers may differ as a result of the weighting process. 



Persons Per Household--A measure obtained by dividing the number of persons

in households by the number of households (or householders). In cases where

persons in households are cross-classified by race or Hispanic origin,

persons in the household are classified by the race or Hispanic origin of

the householder rather than the race or Hispanic origin of each individual.



Relationship to Householder



Householder--The data on relationship to householder were derived from

answers to questionnaire item 2, which was asked of all persons in housing

units.  One person in each household is designated as the householder. In

most cases, this is the person, or one of the persons, in whose name the

home is owned, being bought, or rented and who is listed in column 1 of

the census questionnaire. If there is no such person in the household,

any adult household member 15 years old and over could be designated as

the householder. 



Households are classified by type according to the sex of the

householder and the presence of relatives. Two types of householders

are distinguished: a family householder and a nonfamily householder. A

family householder is a householder living with one or more persons

related to him or her by birth, marriage, or adoption. The householder

and all persons in the household related to him or her are family

members. A nonfamily householder is a householder living alone or with

nonrelatives only. 



Spouse--Includes a person married to and living with a householder. This

category includes persons in formal marriages, as well as persons in

common-law marriages. 



The number of spouses is equal to the number of "married-couple families"

or "married-couple households" in 100-percent tabulations. The number of

spouses, however, is generally less than half of the number of "married

persons with spouse present" in sample tabulations, since more than one

married couple can live in a household, but only spouses of householders

are specifically identified as "spouse." For sample tabulations, the number

of "married persons with spouse present" includes married-couple

subfamilies and married-couple families. 



Child--Includes a son or daughter by birth, a stepchild, or adopted child

of the householder, regardless of the child's age or marital status. The

category excludes sons-in-law, daughters-in-law, and foster children. 



Natural-Born or Adopted Son/Daughter--A son or daughter of the householder

by birth, regardless of the age of the child. Also, this category includes

sons or daughters of the householder by legal adoption, regardless of the

age of the child. If the stepson/stepdaughter of the householder has been

legally adopted by the householder, the child is still classified as a

stepchild. 



Stepson/Stepdaughter--A son or daughter of the householder through marriage

but not by birth, regardless of the age of the child. If the

stepson/stepdaughter of the householder has been legally adopted by the

householder, the child is still classified as a stepchild. 



Own Child--A never-married child under 18 years who is a son or daughter by

birth, a stepchild, or an adopted child of the householder. In certain

tabulations, own children are further classified as living with two parents

or with one parent only. Own children of the householder living with two

parents are by definition found only in married-couple families. 



In a subfamily, an "own child" is a never-married child under 18

years of age who is a son, daughter, stepchild, or an adopted child of

a mother in a mother-child subfamily, a father in a father-child subfamily,

or either spouse in a married-couple subfamily. 



"Related children" in a family include own children and all other persons

under 18 years of age in the household, regardless of marital status, who

are related to the householder, except the spouse of the householder.

Foster children are not included since they are not related to the

householder. 



Other Relatives--In tabulations, includes any household member related to

the householder by birth, marriage, or adoption, but not included

specifically in another relationship category. In certain detailed

tabulations, the following categories may be shown: 



Grandchild--The grandson or granddaughter of the householder. 



Brother/Sister--The brother or sister of the householder, including

stepbrothers, stepsisters, and brothers and sisters by adoption. Brothers-

in-law and sisters-in-law are included in the "Other relative" category on

the questionnaire. 



Parent--The father or mother of the householder, including a stepparent or

adoptive parent. Fathers-in-law and mothers-in-law are included in the

"Other relative" category on the questionnaire. 



Other Relatives--Anyone not listed in a reported category above who is

related to the householder by birth, marriage, or adoption (brother-in-law,

grandparent, nephew, aunt, mother-in-law, daughter-in-law, cousin, and so

forth).



Nonrelatives--Includes any household member, including foster children not

related to the householder by birth, marriage, or adoption. The following

categories may be presented in more detailed tabulations:



   Roomer, Boarder, or Foster Child--Roomer, boarder, lodger, and foster

   children or foster adults of the householder.  



   Housemate or Roommate--A person who is not related to the householder

   and who shares living quarters primarily in order to share expenses. 



   Unmarried Partner--A person who is not related to the householder, who

   shares living quarters, and who has a close personal relationship with

   the householder. 



   Other Nonrelatives--A person who is not related by birth, marriage, or

   adoption to the householder and who is not described by the categories

   given above. 



When relationship is not reported for an individual, it is imputed

according to the responses for age, sex, and marital status for that

person while maintaining consistency with responses for other

individuals in the household. (For more information on imputation, see

Appendix C, Accuracy of the Data.) 



Unrelated Individual--An unrelated individual is: (1) a householder living

alone or with nonrelatives only, (2) a household member who is not related

to the householder, or (3) a person living in group quarters who is not an

inmate of an institution. 



Family Type--A family consists of a householder and one or more other

persons living in the same household who are related to the householder by

birth, marriage, or adoption. All persons in a household who are

related to the householder are regarded as members of his or her

family. A household can contain only one family for purposes of census

tabulations. Not all households contain families since a household may

comprise a group of unrelated persons or one person living alone. 



Families are classified by type as either a "married-couple family" or

"other family" according to the sex of the householder and the presence of

relatives. The data on family type are based on answers to questions on sex

and relationship which were asked on a 100-percent basis. 



Married-Couple Family--A family in which the householder and his or her

spouse are enumerated as members of the same household. 



Other Family: 



   Male Householder, No Wife Present--A family with a male

   householder and no spouse of householder present. 



   Female Householder, No Husband Present--A family with a

   female householder and no spouse of householder present. 



Persons Per Family--A measure obtained by dividing the number of persons in

families by the total number of families (or family householders). In cases

where the measure, "persons in family" or "persons per family" are

cross-tabulated by race or Hispanic origin, the race or Hispanic origin

refers to the householder rather than the race or Hispanic origin of

each individual. 



Subfamily--A subfamily is a married couple (husband and wife enumerated as

members of the same household) with or without never-married children

under 18 years old, or one parent with one or more never-married

children under 18 years old, living in a household and related to, but

not including, either the householder or the householder's spouse. The

number of subfamilies is not included in the count of families, since

subfamily members are counted as part of the householder's family. 



Subfamilies are defined during processing of sample data. In selected

tabulations, subfamilies are further classified by type: married-couple

subfamilies, with or without own children; mother-child subfamilies;

and father-child subfamilies. 



Lone parents include people maintaining either one-parent families or one-

parent subfamilies. Married couples include husbands and wives in both

married-couple families and married-couple subfamilies. 



Unmarried-Partner Household--An unmarried-partner household is a household

other than a "married-couple household" that includes a householder and an

"unmarried partner." An "unmarried partner" can be of the same sex or of

the opposite sex of the householder. An "unmarried partner" in an

"unmarried- partner household" is an adult who is unrelated to the

householder, but shares living quarters and has a close personal

relationship with the householder. 



Unmarried-Couple Household--An unmarried-couple household is composed of

two unrelated adults of the opposite sex (one of whom is the householder)

who share a housing unit with or without the presence of children under 15

years old. 



Foster Children--Foster children are nonrelatives of the householder and

are included in the category, "Roomer, boarder, or foster child" on the

questionnaire. Foster children are identified as persons under 18 years

old and living in households that have no nonrelatives 18 years old and

over (who might be parents of the nonrelatives under 18 years old). 



Stepfamily--A stepfamily is a "married-couple family" with at least one

stepchild of the householder present, where the householder is the

husband. 



Comparability--The 1990 definition of a household is the same as that used

in 1980.  The 1980 relationship category "Son/daughter" has been replaced

by two categories, "Natural-born or adopted son/daughter" and "Stepson/

stepdaughter." "Grandchild" has been added as a separate category. The 1980

nonrelative categories: "Roomer, boarder" and "Partner, roommate" have been

replaced by the categories "Roomer, boarder, or foster child," "Housemate,

roommate," and "Unmarried partner." The 1980 nonrelative category "Paid

employee" has been dropped. 



INCOME IN 1989--The data on income in 1989 were derived from answers to

questionnaire items 32 and 33. Information on money income received in

the calendar year 1989 was requested from persons 15 years old and

over. "Total income" is the algebraic sum of the amounts reported

separately for wage or salary income; net nonfarm self-employment

income; net farm self-employment income; interest, dividend, or net

rental or royalty income; Social Security or railroad retirement

income; public assistance or welfare income; retirement or disability

income; and all other income. "Earnings" is defined as the

algebraic sum of wage or salary income and net income from farm and

nonfarm self-employment. "Earnings" represent the amount of

income received regularly before deductions for personal income taxes,

Social Security, bond purchases, union dues, medicare deductions, etc. 



Receipts from the following sources are not included as income: money

received from the sale of property (unless the recipient was engaged in

the business of selling such property); the value of income "in

kind" from food stamps, public housing subsidies, medical care,

employer contributions for persons, etc.; withdrawal of bank deposits;

money borrowed; tax refunds; exchange of money between relatives living

in the same household; gifts and lump-sum inheritances, insurance

payments, and other types of lump-sum receipts. 



Income Type in 1989--The eight types of income reported in the census are

defined as follows: 



   Wage or Salary Income--Includes total money earnings

   received for work performed as an employee during the calendar year

   1989. It includes wages, salary, Armed Forces pay, commissions, tips,

   piece-rate payments, and cash bonuses earned before deductions were made

   for taxes, bonds, pensions, union dues, etc. 



   Nonfarm Self-Employment Income--Includes net money income (gross

   receipts minus expenses) from one's own business, professional

   enterprise, or partnership. Gross receipts include the value of all

   goods sold and services rendered. Expenses includes costs of goods

   purchased, rent, heat, light, power, depreciation charges, wages and

   salaries paid, business taxes (not personal income taxes), etc. 



   Farm Self-Employment Income--Includes net money income (gross receipts

   minus operating expenses) from the operation of a farm by a person on

   his or her own account, as an owner, renter, or sharecropper. Gross

   receipts include the value of all products sold, government farm

   programs, money received from the rental of farm equipment to others,

   and incidental receipts from the sale of wood, sand, gravel, etc.

   Operating expenses include cost of feed, fertilizer, seed, and other

   farming supplies, cash wages paid to farmhands, depreciation charges,

   cash rent, interest on farm mortgages, farm building repairs, farm taxes

   (not State and Federal personal income taxes), etc. The value of fuel,

   food, or other farm products used for family living is not included as

   part of net income. 



   Interest, Dividend, or Net Rental Income--Includes interest on savings

   or bonds, dividends from stockholdings or membership in associations,

   net income from rental of property to others and receipts from boarders

   or lodgers, net royalties, and periodic payments from an estate or trust

   fund. 



   Social Security Income--Includes Social Security pensions and survivors

   benefits and permanent disability insurance payments made by the Social

   Security Administration prior to deductions for medical insurance, and

   railroad retirement insurance checks from the U.S. Government. Medicare

   reimbursements are not included. 



   Public Assistance Income--Includes: (1) supplementary security income

   payments made by Federal or State welfare agencies to low income persons

   who are aged (65 years old or over), blind, or disabled; (2) aid to

   families with dependent children, and (3) general assistance. Separate

   payments received for hospital or other medical care (vendor payments)

   are excluded from this item. 



   Retirement or Disability Income--Includes: (1) retirement pensions and

   survivor benefits from a former employer, labor union, or Federal,

   State, county, or other governmental agency; (2) disability income from

   sources such as worker's compensation; companies or unions; Federal,

   State, or local government; and the U.S. military; (3) periodic receipts

   from annuities and insurance; and (4) regular income from IRA and KEOGH

   plans. 



   All Other Income--Includes unemployment compensation, Veterans

   Administration (VA) payments, alimony and child support, 

   contributions received periodically from persons not living in the

   household, military family allotments, net gambling winnings, and other

   kinds of periodic income other than earnings. 



Income of Households--Includes the income of the householder and all other

persons 15 years old and over in the household, whether related to the

householder or not. Because many households consist of only one person,

average household income is usually less than average family income. 



Income of Families and Persons--In compiling statistics on family income,

the incomes of all members 15 years old and over in each family are summed

and treated as a single amount. However, for persons 15 years old and over,

the total amounts of their own incomes are used. Although the income

statistics covered the calendar year 1989, the characteristics of persons

and the composition of families refer to the time of enumeration (April

1990).  Thus, the income of the family does not include amounts received by

persons who were members of the family during all or part of the

calendar year 1989 if these persons no longer resided with the family

at the time of enumeration. Yet, family income amounts reported by

related persons who did not reside with the family during 1989 but who

were members of the family at the time of enumeration are included.

However, the composition of most families was the same during 1989 as

in April 1990. 



Median Income--The median divides the income distribution into two equal

parts, one having incomes above the median and the other having incomes

below the median. For households and families, the median income is based

on the distribution of the total number of units including those with no

income. The median for persons is based on persons with income. The

median income values for all households, families, and persons are

computed on the basis of more detailed income intervals than shown in

most tabulations. Median household or family income figures of $50,000

or less are calculated using linear interpolation. For persons,

corresponding median values of $40,000 or less are also computed using

linear interpolation. All other median income amounts are derived

through Pareto interpolation. (For more information on medians and

interpolation, see the discussion under "Derived Measures.") 



Mean Income--This is the amount obtained by dividing the total income of a

particular statistical universe by the number of units in that universe.

Thus, mean household income is obtained by dividing total household income

by the total number of households. For the various types of income the

means are based on households having those types of income. "Per capita

income" is the mean income computed for every man, woman, and child in a

particular group. It is derived by dividing the total income of a

particular group by the total population in that group. 



Care should be exercised in using and interpreting mean income values

for small subgroups of the population. Because the mean is influenced

strongly by extreme values in the distribution, it is especially

susceptible to the effects of sampling variability, misreporting, and

processing errors. The median, which is not affected by extreme values,

is, therefore, a better measure than the mean when the population base

is small. The mean, nevertheless, is shown in some data products for

most small subgroups because, when weighted according to the number of

cases, the means can be added to obtained summary measures for areas

and groups other than those shown in census tabulations. 



Limitation of the Data--Since questionnaire entries for income frequently

are based on memory and not on records, many persons tended to forget minor

or irregular sources of income and, therefore, underreport their income.

Underreporting tends to be more pronounced for income sources that are

not derived from earnings, such as Social Security, public assistance,

or from interest, dividends, and net rental income. 



There are errors of reporting due to the misunderstanding of the income

questions such as reporting gross rather than net dollar amounts for

the two questions on net self-employment income, which resulted in an

overstatement of these items. Another common error is the reporting of

identical dollar amounts in two of the eight type of income items where

a respondent with only one source of income assumed that the second

amount should be entered to represent total income. Such instances of

overreporting had an impact on the level of mean nonfarm or farm

self-employment income and mean total income published for the various

geographical subdivisions of the State. 



Extensive computer editing procedures were instituted in the data

processing operation to reduce some of these reporting errors and to

improve the accuracy of the income data. These procedures corrected

various reporting deficiencies and improved the consistency of reported

income items associated with work experience and information on

occupation and class of worker. For example, if persons reported they

were self-employed on their own farm, not incorporated, but had

reported wage and salary earnings only, the latter amount was shifted

to net farm self-employment income. Also, if any respondent reported total

income only, the amount was generally assigned to one of the type of income

items according to responses to the work experience and class-of-worker

questions. Another type of problem involved nonreporting of income

data. Where income information was not reported, procedures were

devised to impute appropriate values with either no income or positive

or negative dollar amounts for the missing entries. (For more

information on imputation, see Appendix C, Accuracy of the Data.) 



In income tabulations for households and families, the lowest income

group (e.g., less than $5,000) includes units that were classified as

having no 1989 income. Many of these were living on income "in

kind," savings, or gifts, were newly created families, or families

in which the sole breadwinner had recently died or left the household.

However, many of the households and families who reported no income

probably had some money income which was not recorded in the census. 



The income data presented in the tabulations covers money income only.

The fact that many farm families receive an important part of their

income in the form of "free" housing and goods produced and

consumed on the farm rather than in money should be taken into

consideration in comparing the income of farm and nonfarm residents.

Nonmoney income such as business expense accounts, use of business

transportation and facilities, or partial compensation by business for

medical and educational expenses was also received by some nonfarm

residents. Many low income families also receive income "in kind"

from public welfare programs. In comparing income data for 1989 with

earlier years, it should be noted that an increase or decrease in money

income does not necessarily represent a comparable change in real

income, unless adjustments for changes in prices are made. 



Comparability--The income data collected in the 1980 and 1970 censuses are 

similar to the 1990 census data, but there are variations in the detail of

the questions. In 1980, income information for 1979 was collected from

persons in approximately 19 percent of all housing units and group

quarters. Each person was required to report: 



     Wage or salary income

     Net nonfarm self-employment income 

     Net farm self-employment income

     Interest, dividend, or net rental or royalty income Social Security

      income 

     Public assistance income

     Income from all other sources 



Between the 1980 and 1990 censuses, there were minor differences in

the processing of the data. In both censuses, all persons with missing

values in one or more of the detailed type of income items

and total income were designated as allocated. Each

missing entry was imputed either as a "no" or as a dollar amount.

If total income was reported and one or more of the type of

income fields was not answered, then the entry in total income

generally was assigned to one of the income types according to the

socioeconomic characteristics of the income recipient. This person was

designated as unallocated. 



In 1980 and 1990, all nonrespondents with income not reported (whether

heads of households or other persons) were assigned the reported income

of persons with similar characteristics. (For more information on

imputation, see Appendix C, "Accuracy of the Data.") 



There was a difference in the method of computer derivation of

aggregate income from individual amounts between the two census

processing operations. In the 1980 census, income amounts less than

$100,000 were coded in tens of dollars, and amounts of $100,000 or more

were coded in thousands of dollars; $5 was added to each amount coded

in tens of dollars and $500 to each amount coded in thousands of

dollars. Entries of $999,000 or more were treated as $999,500 and

losses of $9,999 or more were treated as minus $9,999. In the 1990

census, income amounts less than $999,999 were keyed in dollars.

Amounts of $999,999 or more were treated as $999,999 and losses of

$9,999 or more were treated as minus $9,999 in all of the computer

derivations of aggregate income. 



In 1970, information on income in 1969 was obtained from all members in

every fifth housing unit and small group quarters (less than 15

persons) and every fifth person in all other group quarters. Each

person was required to report: 



     Wage or salary income 

     Net nonfarm self-employment income 

     Net farm self-employment income 

     Social Security or Railroad Retirement 

     Public assistance or welfare payments 

     Income from all other sources



If a person reported a dollar amount in wage or salary, net nonfarm

self-employment income, or net farm self-employment income, the person was

considered as unallocated only if no further dollar amounts were imputed

for any additional missing entries.



In 1960, data on income were obtained from all members in every fourth

housing unit and from every fourth person 14 years old and over living

in group quarters. Each person was required to report wage or salary

income, net self-employment income, and income other than earnings

received in 1959. An assumption was made in the editing process that no

other type of income was received by a person who reported the receipt

of either wage and salary income or self-employment but who had failed

to report the receipt of other money income. 



For several reasons, the income data shown in census tabulations are

not directly comparable with those that may be obtained from

statistical summaries of income tax returns. Income, as defined for

Federal tax purposes, differs somewhat from the Census Bureau concept.

Moreover, the coverage of income tax statistics is different because of

the exemptions of persons having small amounts of income and the

inclusion of net capital gains in tax returns. Furthermore, members of

some families file separate returns and others file joint returns;

consequently, the income reporting unit is not consistently either a

family or a person. 



The earnings data shown in census tabulations are not directly

comparable with earnings records of the Social Security Administration.

The earnings record data for 1989 excluded the earnings of most

civilian government employees, some employees of nonprofit

organizations, workers covered by the Railroad Retirement Act, and

persons not covered by the program because of insufficient earnings.

Furthermore, earnings received from any one employer in excess of

$48,000 in 1989 are not covered by earnings records. Finally, because

census data are obtained from household questionnaires, they may differ

from Social Security Administration earnings record data, which are

based upon employers' reports and the Federal income tax returns of

self-employed persons. 



The Bureau of Economic Analysis (BEA) of the Department of Commerce

publishes annual data on aggregate and per-capita personal income

received by the population for States, metropolitan areas, and selected

counties. Aggregate income estimates based on the income statistics

shown in census products usually would be less than those shown in the

BEA income series for several reasons. The Census Bureau data are

obtained directly from households, whereas the BEA income series is

estimated largely on the basis of data from administrative records of

business and governmental sources. Moreover, the definitions of income

are different. The BEA income series includes some items not included

in the income data shown in census publications, such as income "in

kind," income received by nonprofit institutions, the value of

services of banks and other financial intermediaries rendered to

persons without the assessment of specific charges, Medicare payments,

and the income of persons who died or emigrated prior to April 1, 1990.

On the other hand, the census income data include contributions for

support received from persons not residing in the same household and

employer contributions for social insurance. 



INDUSTRY, OCCUPATION, AND CLASS OF WORKER--The data on industry,

occupation, and class of worker were derived from answers to questionnaire

items 28, 29, and 30 respectively. These questions were asked of a sample

of persons. Information on industry relates to the kind of business

conducted by a person's employing organization; occupation describes the

kind of work the person does on the job. 



For employed persons, the data refer to the person's job during the

reference week. For those who worked at two or more jobs, the data

refer to the job at which the person worked the greatest number of

hours. For unemployed persons, the data refer to their last job. The

industry and occupation statistics are derived from the detailed

classification systems developed for the 1990 census as described

below. The Classified Index of Industries and Occupations

provided additional information on the industry and occupation

classification systems. 



Respondents provided the data for the tabulations by writing on the

questionnaires descriptions of their industry and occupation. These

descriptions were keyed and passed through automated coding software

which assigned a portion of the written entries to categories in the

classification system. The automated system assigned codes to 59

percent of the industry entries and 38 percent of the occupation

entries. 



Those cases not coded by the computer were referred to clerical staff

in the Census Bureau's Kansas City processing office for coding. The

clerical staff converted the written questionnaire descriptions to

codes by comparing these descriptions to entries in the

Alphabetical Index of Industries and Occupations. For the

industry code, these coders also referred to an Employer Name List

(formerly called Company Name List). This list, prepared from the

Standard Statistical Establishment List developed by the Census Bureau

for the economic censuses and surveys, contained the names of business

establishments and their Standard Industrial Classification (SIC) codes

converted to population census equivalents. This list facilitated

coding and maintained industrial classification comparability. 



Industry--The industry classification system developed for the 1990 census

consists of 235 categories for employed persons, classified into 13

major industry groups. Since 1940, the industrial classification has

been based on the Standard Industrial Classification Manual (SIC). The

1990 census classification was developed from the 1987 SIC published by

the Office of Management and Budget Executive Office of the President. 



The SIC was designed primarily to classify establishments by the type

of industrial activity in which they were engaged. However, census

data, which were collected from households, differ in detail and nature

from those obtained from establishment surveys. Therefore, the census

classification systems, while defined in SIC terms, cannot reflect the

full detail in all categories. There are several levels of industrial

classification found in census products. For example, the 1990 CP-2,

Social and Economic Characteristics report includes 41

unique industrial categories, while the 1990 Summary Tape File 4 (STF

4) presents 72 categories. 



Occupation--The occupational classification system developed for the 1990

census consists of 500 specific occupational categories for employed

persons arranged into 6 summary and 13 major occupational groups. This

classification was developed to be consistent with the Standard

Occupational Classification (SOC) Manual: 1980, published by the Office

of Federal Statistical Policy and Standards, U.S. Department of

Commerce. Tabulations with occupation as the primary characteristic

present several levels of occupational detail. The most detailed

tabulations are shown in a special 1990 subject report and tape files

on occupation. These products contain all 500 occupational categories

plus industry or class of worker subgroupings of occupational

categories. 



Some occupation groups are related closely to certain industries.

Operators of transportation equipment, farm operators and workers, and

private household workers account for major portions of their

respective industries of transportation, agriculture, and private

households. However, the industry categories include persons in other

occupations. For example, persons employed in agriculture include truck

drivers and bookkeepers; persons employed in the transportation

industry include mechanics, freight handlers, and payroll clerks; and

persons employed in the private household industry include occupations

such as chauffeur, gardener, and secretary. 



Class of Worker--The data on class of worker were derived from answers to

questionnaire item 30. The information on class of worker refers to the

same job as a respondent's industry and occupation and categorizes

persons according to the type of ownership of the employing

organization. The class of worker categories are defined as follows: 



   Private Wage and Salary Workers--Includes persons who worked for wages,

   salary, commission, tips, pay-in-kind, or piece rates for a private for

   profit employer or a private not-for-profit, tax-exempt or charitable

   organization. Self-employed persons whose business was incorporated are

   included with private wage and salary workers because they are paid

   employees of their own companies. Some tabulations present data

   separately for these subcategories: "For profit," "Not for profit," and

   "Own business incorporated." 



   Employees of foreign governments, the United Nations, or other formal

   international organizations were classified as "Private-not-for-profit."



   Government Workers--Includes persons who were employees of any local,

   State, or Federal governmental unit, regardless of the activity of the

   particular agency. For some tabulations, the data were presented

   separately for the three levels of government. 



   Self-Employed Workers--Includes persons who worked for profit or fees in

   their own unincorporated business, profession, or trade, or who operated

   a farm. 



   Unpaid Family Workers--Includes persons who worked 15 hours or more

   without pay in a business or on a farm operated by a relative. 



   Salaried/Self-Employed--In tabulations that categorize persons as either

   salaried or self-employed, the salaried category includes private and

   government wage and salary workers; self-employed includes self-employed

   persons and unpaid family workers. 



   The industry category, "Public administration," is limited to regular

   government functions such as legislative, judicial, administrative, and

   regulatory activities of governments. Other government organizations

   such as schools, hospitals, liquor stores, and bus lines are classified

   by industry according to the activity in which they are engaged. On the

   other hand, the class of worker government categories include all

   government workers. 



Occasionally respondents supplied industry, occupation, or class of

worker descriptions which were not sufficiently specific for precise

classification or did not report on these items at all. Some of these

cases were corrected through the field editing process and during the

coding and tabulation operations. In the coding operation, certain

types of incomplete entries were corrected using the Alphabetical

Index of Industries and Occupations. For example, it was possible

in certain situations to assign an industry code based on the

occupation reported. 



Following the coding operations, there was a computer edit and an

allocation process. The edit first determined whether a respondent was

in the universe which required an industry and occupation code. The

codes for the three items (industry, occupation, and class of worker)

were checked to ensure they were valid and were edited for their

relation to each other. Invalid and inconsistent codes were either

blanked or changed to a consistent code. 



If one or more of the three codes were blank after the edit, a code was

assigned from a "similar" person based on other items such as

age, sex, education, farm or nonfarm residence, and weeks worked. If

all the labor force and income data also were blank, all these economic

items were assigned from one other person who provided all the

necessary data. 



Comparability--Comparability of industry and occupation data was affected

by a number of factors, primarily the systems used to classify the

questionnaire responses. For both the industry and occupation

classification systems, the basic structures were generally the same from

1940 to 1970, but changes in the individual categories limited

comparability of the data from one census to another. These changes were

needed to recognize the "birth" of new industries and occupations, the

"death" of others, and the growth and decline in existing industries and

occupations, as well as, the desire of analysts and other users for

more detail in the presentation of the data. Probably the greatest

cause of incomparability is the movement of a segment of a category to

a different category in the next census. Changes in the nature of jobs

and respondent terminology, and refinement of category composition made

these movements necessary. 



In the 1990 census, the industry classification had minor revisions to

reflect recent changes to the SIC. The 1990 occupational classification

system is essentially the same as that for the 1980 census. However,

the conversion of the census classification to the SOC in 1980 meant

that the 1990 classification system was less comparable to the

classifications used prior to the 1980 census. 



Other factors that affected data comparability included the universe to

which the data referred (in 1970, the age cutoff for labor force was

changed from 14 years to 16 years); how the industry and occupation

questions were worded on the questionnaire (for example, important

changes were made in 1970); improvements in the coding procedures (the

Employer Name List technique was introduced in 1960); and how the

"not reported" cases are handled. Prior to 1970, they were placed

in the residual categories, "Industry not reported" and

"Occupation not reported." In 1970, an allocation process was

introduced that assigned these cases to major groups. In 1990, as in

1980, the "Not reported" cases were assigned to individual

categories. Therefore, the 1980 and 1990 data for individual categories

included some numbers of persons who were tabulated in a "Not

reported" category in previous censuses. 



The following publications contain information on the various factors

affecting comparability and are particularly useful for understanding

differences in the occupation and industry information from earlier

censuses: U.S. Bureau of the Census, Changes Between the 1950 and

1960 Occupation and Industry Classifications With Detailed Adjustments

of 1950 Data to the 1960 Classifications, Technical Paper No. 18,

1968; U.S. Bureau of the Census, 1970 Occupation and Industry

Classification Systems in Terms of their 1960 Occupation and Industry

Elements, Technical Paper No. 26, 1972; and U.S. Bureau of the

Census, The Relationship Between the 1970 and 1980 Industry and

Occupation Classification Systems, Technical Paper No. 59, 1988.

For citations for earlier census years, see the 1980 Census of

Population report, PC80-1-D, Detailed Population

Characteristics. 



The 1990 census introduced an additional class of worker category for

"private not-for-profit" employers. This category is a subset of

the 1980 category "employee of private employer" so there is no

comparable data before 1990. Also in 1990, employees of foreign

governments, the United Nations, etc., are classified as "private

not-for-profit," rather than Federal Government as in 1970 and 1980. While

in theory, there was a change in comparability, in practice, the small

number of U.S. residents working for foreign governments made this

change negligible. 



Comparability between the statistics on industry and occupation from

the 1990 census and statistics from other sources is affected by many

of the factors described in the section on "Employment Status."

These factors are primarily geographic differences between residence

and place of work, different dates of reference, and differences in

counts because of dual job holding. Industry data from population

censuses cover all industries and all kinds of workers, whereas, data

from establishments often excluded private household workers,

government workers, and the self-employed. Also, the replies from

household respondents may have differed in detail and nature from those

obtained from establishments. 



Occupation data from the census and data from government licensing

agencies, professional associations, trade unions, etc., may not be as

comparable as expected. Organizational listings often include persons

not in the labor force or persons devoting all or most of their time to

another occupati