Definition of Poverty in the IPUMS Samples
Poverty data in the IPUMS are based on a definition established by the Social Security Administration in 1964 and subsequently modified by Federal interagency committees in 1969 and 1980. The Office of Management and Budget's (OMB) Directive 14 prescribes this definition as the official poverty measure for federal agencies to use in their statistical work.
At the core of this definition was the 1961 economy food plan, the least costly of four nutritionally adequate food plans designed by the Department of Agriculture. It was determined from the Agriculture Department's 1955 survey of food consumption that families of three or more persons spend approximately one-third of their income on food; hence, the poverty level for these families was set at three times the cost of the economy food plan. For smaller families and persons living alone, the cost of the economy food plan was multiplied by factors that were slightly higher to compensate for the relatively larger fixed expenses for these smaller households. For a more thorough description of how poverty thresholds were created and changed over time, see Gordon M. Fisher's The Development and History of Poverty Thresholds, available here.
The income cutoffs used to determine the poverty status of families and unrelated individuals include a set of 48 thresholds arranged in a two-dimensional matrix consisting of family size (from one person to nine or more persons) cross-classified by presence and number of family members under 18 years old (from no children present to eight or more children present). Unrelated individuals and two-person families were further differentiated by age of the householder (under 65 years old and 65 years old and over). The total income of each family or unrelated individual in the sample was tested against the appropriate poverty threshold to determine the poverty status of that family or unrelated individual.
The federally established poverty thresholds are revised annually to allow for changes in the cost of living as reflected in the Consumer Price Index (CPI-U). The IPUMS relies on the poverty matrix from 1999, making necessary adjustments to other years' data to account for inflation. For each year, IPUMS multiplies total family income (FTOTINC) by the following factors and then uses the resulting adjusted total family income to calcuate poverty status:
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, Series P-60, No. 210, Poverty in the United States: 1999.
Poverty Thresholds by Size of Family and Number of Children Under 18 Years, 1999 dollars (Average of the 12 Monthly Values)
|Number of people||Number of related children|
|One person under 65 years||$8,667|
|One person, 65 years or older||7,990|
|Two people, RP under 65 years||11,156||$11,483|
|Two people, RP 65 years or older||10,070||11,440|
|Nine or more people||36,897||37,076||36,583||36,169||35,489||34,554||33,708||33,499||$32,208|
Source: U.S. Census Bureau, Demographic Surveys Division, Continuous Measurement Office.