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Data Dictionary: Census 2000
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Survey: Census 2000
Data Source: U.S. Census Bureau
Universe: Unrelated individuals for whom poverty status is determined
Relevant Documentation:
Excerpt from: Social Explorer, U.S. Census Bureau; 2000 Census of Population and Housing, Summary File 3: Technical Documentation, 2002.
Poverty Status in 1999
The poverty data were derived from answers to long-form questionnaire Items 31 and 32, the same questions used to derive income data. (For more information, see "Income in 1999.") The Census Bureau uses the federal governments official poverty definition. The Social Security Administration (SSA) developed the original poverty definition in 1964, which federal interagency committees subsequently revised in 1969 and 1980. The Office of Management and Budgets (OMBs) Directive 14 prescribes this definition as the official poverty measure for federal agencies to use in their statistical work.

Derivation of the Current Poverty Measure
When the Social Security Administration (SSA) created the poverty definition in 1964, it focused on family food consumption. The U.S. Department of Agriculture (USDA) used its data about the nutritional needs of children and adults to construct food plans for families. Within each food plan, dollar amounts varied according to the total number of people in the family and the familys composition, such as the number of children within each family. The cheapest of these plans, the Economy Food Plan, was designed to address the dietary needs of families on an austere budget. Since the USDAs 1955 Food Consumption Survey showed that families of three or more people across all income levels spent roughly one-third of their income on food, the SSA multiplied the cost of the Economy Food Plan by three to obtain dollar figures for the poverty thresholds. Since the Economy Food Plan budgets varied by family size and composition, so too did the poverty thresholds. For 2-person families, the thresholds were adjusted by slightly higher factors because those households had higher fixed costs. Thresholds for unrelated individuals were calculated as a fixed proportion of the corresponding thresholds for 2-person families.

The poverty thresholds are revised annually to allow for changes in the cost of living as reflected in the Consumer Price Index (CPI-U). The poverty thresholds are the same for all parts of the country - they are not adjusted for regional, state or local variations in the cost of living. For a detailed discussion of the poverty definition, see U.S. Census Bureau, Current Population Reports, " Poverty in the United States: 1999," P-60-210.

How Poverty Status is Determined
The poverty status of families and unrelated individuals in 1999 was determined using 48 thresholds (income cutoffs) arranged in a two dimensional matrix. The matrix consists of family size (from 1 person to 9 or more people) cross-classified by presence and number of family members under 18 years old (from no children present to 8 or more children present). Unrelated individuals and 2-person families were further differentiated by the age of the reference person (RP) (under 65 years old and 65 years old and over).

To determine a person's poverty status, one compares the persons total family income with the poverty threshold appropriate for that persons family size and composition (see table below). If the total income of that persons family is less than the threshold appropriate for that family, then the person is considered poor, together with every member of his or her family. If a person is not living with anyone related by birth, marriage, or adoption, then the persons own income is compared with his or her poverty threshold.

Weighted average thresholds
Even though the official poverty data are based on the 48 thresholds arranged by family size and number of children within the family, data users often want to get an idea of the "average" threshold for a given family size. The weighted average thresholds provide that summary. They are weighted averages because for any given family size, families with a certain number of children may be more or less common than families with a different number of children. In other words, among 3-person families, there are more families with two adults and one child than families with three adults. To get the weighted average threshold for families of a particular size, multiply each threshold by the number of families for whom that threshold applies; then add up those products, and divide by the total number of families who are of that family size.

For example, for 3-person families, 1999 weighted thresholds were calculated in the following way using information from the 2000 Current Population Survey:

Family type Number of families Threshold  
No children (three adults) 5,213 * $13,032 = $67,935,816
One child (two adults) 8,208 * $13,410 = $110,069,280
Two children (one adult) 2,656 * $13,423 = $35,651,488
Totals 16,077       $213,656,584
Source: Current Population Survey, March 2000.

Dividing $213,656,584 by 16,077 (the total number of 3-person families) yields $13,290, the weighted average threshold for 3-person families. Please note that the thresholds are weighted not just by the number of poor families, but by all families for which the thresholds apply: the thresholds are used to determine which families are at or above poverty, as well as below poverty.

Individuals for whom poverty status is determined
Poverty status was determined for all people except institutionalized people, people in military group quarters, people in college dormitories, and unrelated individuals under 15 years old. These groups also were excluded from the numerator and denominator when calculating poverty rates. They are considered neither "poor" nor "nonpoor."

Specified poverty levels
For various reasons, the official poverty definition does not satisfy all the needs of data users. Therefore, some of the data reflect the number of people below different percentages of the poverty level. These specified poverty levels are obtained by multiplying the official thresholds by the appropriate factor. For example, the average income cutoff at 125 percent of the poverty level was $21,286 ($17,029 x 1.25) in 1999 for family of four people.

Poverty Threshold in 1999, by Size of Family and Number of Related Children Under 18 Years Old (Dollars)
Size of family unit Weighted average threshold Related children under 18 years old
    None One Two Three Four Five Six Seven Eight or more
One person (unrelated individual) 8501                  
    Under 65 years old 8667 8667                
    65 years old and over 7990 7990                
Two people 10869                  
    Householder under 65 years old 11214 11156 11483              
    Householder 65 years old and over 10075 10070 11440              
Three people 13290 13032 13410 13423            
Four people 17029 17184 17465 16895 16954          
Five people 20127 20723 21024 20380 19882 19578        
Six people 22727 23835 23930 23436 22964 22261 21845      
Seven people 25912 27425 27596 27006 26595 25828 24934 23953    
Eight people 28967 30673 30944 30387 29899 29206 28327 27412 27180  
Nine people or more 34417 36897 37076 36583 36169 35489 34554 33708 33499 32208

Income deficit
Income deficit represents the difference between the total income of families and unrelated individuals below the poverty level and their respective poverty thresholds. In computing the income deficit, families reporting a net income loss are assigned zero dollars and for such cases the deficit is equal to the poverty threshold. This measure provides an estimate of the amount which would be required to raise the incomes of all poor families and unrelated individuals to their respective poverty thresholds. The income deficit is thus a measure of the degree of the impoverishment of a family or unrelated individual. However, please use caution when comparing the average deficits of families with different characteristics. Apparent differences in average income deficits may, to some extent, be a function of differences in family size.

Aggregate income deficit
Aggregate income deficit refers only to those families or unrelated individuals who are classified as below the poverty level. It is defined as the group (e.g., type of family) sum total of differences between the appropriate threshold and total family income or total personal income. Aggregate income deficit is subject to rounding, which means that all cells in a matrix are rounded to the nearest hundred dollars. (For more information, see "Aggregate" under "Derived Measures".)

Mean income deficit
Mean income deficit represents the amount obtained by dividing the total income deficit for a group below the poverty level by the number of families (or unrelated individuals) in that group. (The aggregate used to calculate mean income deficit is rounded. For more information, see "Aggregate income deficit.") As mentioned above, please use caution when comparing mean income deficits of families with different characteristics, as apparent differences may to some extent be a function of differences in family size. Mean income deficit is rounded to the nearest whole dollar. (For more information on means, see "Derived Measures".)

The poverty definition used in the 1980 census and later differed slightly from the one used in the 1970 census. Three technical modifications were made to the definition used in the 1970 census:

1. Beginning with the 1980 census, the Office of Management and Budget eliminated any distinction between thresholds for "families with a female householder with no husband present" and all other families. The new thresholds - which apply to all families regardless of the householder's sex - were a weighted average of the old thresholds.

2. The Office of Management and Budget eliminated any differences between farm families and nonfarm families, and farm and nonfarm unrelated individuals. In the 1970 census, the farm thresholds were 85 percent of those for nonfarm families; whereas, in 1980 and later, the same thresholds were applied to all families and unrelated individuals regardless of residence.

3. The thresholds by size of family were extended from seven or more people in 1970 to nine or more people in 1980 and later.

These changes resulted in a minimal increase in the number of poor at the national level. For a complete discussion of these modifications and their impact, see U.S. Census Bureau, Current Population Reports, " Characteristics of the Population Below the Poverty Level: 1980," P-60, No. 133.

With respect to poverty, the population covered in the 1970 census was almost the same as that covered in the 1980 census and later. The only difference was that in 1980 and after, unrelated individuals under 15 years old were excluded from the poverty universe, while in 1970, only those under age 14 were excluded. The limited poverty data from the 1960 census excluded all people in group quarters and included all unrelated individuals regardless of age. It was unlikely that these differences in population coverage would have had significant impact when comparing the poverty data for people since the 1960 census.

Current Population Survey
Because the questionnaires and data collection procedures differ, Census 2000 estimates of the number of people below the poverty level by various characteristics may differ from those reported in the March 2000 Current Population Survey. Please refer to more details.

Household poverty data
Poverty status is not defined for households - only for families and unrelated individuals. Because some data users need poverty data at the household level, we have provided a few matrices that show tallies of households by the poverty status of the householder. In these matrices, the householder's poverty status is computed exactly the same way as described above. Therefore, to determine whether or not a "household" was in poverty, anyone who is not related to the householder is ignored.

Example #1: Household #1 has six members - a married couple, Alice and Albert, with their 10-year-old nephew, Aaron, and another married couple, Brian and Beatrice, with their 6-year-old son, Ben. Alice is the householder. Brian, Beatrice, and Ben are not related to Alice.

Household member Relationship to Alice Income
Alice self (householder) $5,000
Albert spouse $40,000
Aaron related child $0
Brian unrelated individual $0
Beatrice unrelated individual $5,000
Ben unrelated individual $0

The total income of Alice's family is $45,000, and their poverty threshold is $13,410, since there are three people in the family, with one member under age 18. Their income is greater than their threshold, so they are not classified as poor. Their ratio of income to poverty is 3.36 ($45,000 divided by $13,410). Alice's income-to-poverty ratio is also 3.36, because everyone in the same family has the same poverty status.
Even though Brian, Beatrice and Ben would be classified as poor if they lived in their own household, the household is not classified as poor because the householder, Alice, is not poor, as was shown in the computation above.

Example #2: Household #2 consists of four adults, Claude, Danielle, Emily, and Francis, who are unrelated to each other and are living as housemates. Claude, who is age 30, is the householder.

Household member Relationship to Claude Income
Claude self (householder) $4,500
Danielle unrelated individual $82,000
Emily unrelated individual $28,000
Francis unrelated individual $40,000

Because Claude is under age 65 and is not living with any family members, his poverty threshold is $8,667. Since his income, $4,500, is less than his threshold, he is considered poor. His ratio of income to poverty is 0.52 ($4,500 divided by $8,667).
Household #2 would be classified as poor because its householder, Claude, is poor, even though the other household members (who are not related to Claude) are not in poverty.

Excerpt from: Social Explorer, U.S. Census Bureau; 2000 Census of Population and Housing, Summary File 3: Technical Documentation, 2002.
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.

Excerpt from: Social Explorer, U.S. Census Bureau; 2000 Census of Population and Housing, Summary File 3: Technical Documentation, 2002.
The data on relationship to householder were derived from the question, "How is this person related to Person 1," which was asked of Persons 2 and higher in housing units. One person in each household is designated as the householder (Person 1). In most cases, the householder is the person, or one of the people, in whose name the home is owned, being bought, or rented. If there is no such person in the household, any adult household member 15 years old and over could be designated as the householder (i.e., Person 1). Households are classified by type according to the sex of the householder and the presence of relatives. Two types of householders are distinguished: family householders and nonfamily householders. A family householder is a householder living with one or more individuals related to him or her by birth, marriage, or adoption. The householder and all of the people in the household related to him or her are family members. A nonfamily householder is a householder living alone or with nonrelatives only.

Excerpt from: Social Explorer, U.S. Census Bureau; 2000 Census of Population and Housing, Summary File 3: Technical Documentation, 2002.
Educational Attainment
Data on educational attainment were derived from answers to long-form questionnaire Item 9, which was asked of a sample of the population. Data on attainment are tabulated for the population 25 years old and over. However, when educational attainment is cross-tabulated by other variables, the universe may change. (For example, when educational attainment is crossed by disability status, the data are tabulated for the civilian noninstitutionalized population 18 to 34 years old.) People are classified according to the highest degree or level of school completed.

The order in which degrees were listed on the questionnaire suggested that doctorate degrees were "higher" than professional school degrees, which were "higher" than master's degrees. The question included instructions for people currently enrolled in school to report the level of the previous grade attended or the highest degree received. Respondents who did not report educational attainment or enrollment level were assigned the attainment of a person of the same age, race, Hispanic or Latino origin, occupation and sex, where possible, who resided in the same or a nearby area. Respondents who filled more than one box were edited to the highest level or degree reported.

The question included a response category that allowed respondents to report completing the 12th grade without receiving a high school diploma. It allowed people 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, to be reported as "high school graduate(s)." The category "Associate degree" included people whose highest degree is an associate degree, which generally requires 2 years of college level work and is either in an occupational program that prepares them for a specific occupation, or an academic program primarily in the arts and sciences. The course work may or may not be transferable to a Bachelor's degree. master's degrees include the traditional MA and MS degrees and field-specific degrees, such as MSW, MEd, MBA, MLS, and MEng. Some examples of professional degrees include medicine, dentistry, chiropractic, optometry, osteopathic medicine, pharmacy, podiatry, veterinary medicine, law, and theology. Vocational and technical training, such as barber school training; business, trade, technical, and vocational schools; or other training for a specific trade, are specifically excluded.

High school graduate or higher
This category includes people whose highest degree was a high school diploma or its equivalent, people who attended college but did not receive a degree, and people who received a college, university, or professional degree. People who reported completing the 12th grade but not receiving a diploma are not high school graduates.

Not enrolled, not high school graduate
This category includes people of compulsory school attendance age or above who were not enrolled in school and were not high school graduates. These people may be referred to as "high school dropouts." However, there is no criterion regarding when they "dropped out" of school, so they may have never attended high school.

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 1950 to 1980 censuses, a two-part question was used to construct highest grade or year of school completed. The question asked (1) the highest grade of school attended and (2) whether that grade was finished. For people who have not attended college, the response categories in the current educational attainment question should produce data that are comparable to data on highest grade completed from earlier censuses. For people who attended college, there is less comparability between years of school completed and highest degree.

Beginning in 1990, the response categories for people 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 1990 census suggests that these terms were more distinct than in earlier decades, and this change may have threatened the ability to estimate the number of "college graduates" from the number of people 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 the 2000 and 1990 censuses with data from the earlier censuses should be made with great caution.

Changes between 1990 and Census 2000 were slight. The two associate degree categories in 1990 were combined into one for Census 2000. "Some college, no degree" was split into two categories, "Some college credit, but less than 1 year," and "1 or more years of college, no degree." Prior to 1990, the college levels reported began with "Completed 1 year of college." Beginning in 1990, the first category was "Some college, no degree," which allowed people with less than 1 year of college to be given credit for college. Prior to 1990, they were included in "High school, 4 years." The two revised categories will accommodate comparisons with either data series and allow the tabulation of students who completed at least 1 year of college, as some data users wish. This will not change the total number who completed some college.

The category "12th grade, no diploma" was counted as high school completion or "Completed high school, 4 years" prior to 1990 and as "Less than high school graduate" in 1990 and 2000. In the 1960 and subsequent censuses, people 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, people for whom educational attainment was not reported were not allocated.

In censuses prior to 1990, "median school years completed" was used as a summary measure of educational attainment. Using the current educational attainment question, 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 that can be calculated from the present data and offer quite readily interpretable measures of differences between population subgroups.