There are two slightly different versions of the federal poverty measure:
* The poverty thresholds, and
* The poverty guidelines.
The poverty thresholds are the original version of the federal poverty measure. They are updated each year by the Census Bureau (although they were originally developed by Mollie Orshansky of the Social Security Administration). The thresholds are used mainly for statistical purposes — for instance, preparing estimates of the number of Americans in poverty each year. (In other words, all official poverty population figures are calculated using the poverty thresholds, not the guidelines.) Poverty thresholds since 1980 and weighted average poverty thresholds since 1959 are available on the Census Bureau’s Web site. For an example of how the Census Bureau applies the thresholds to a family’s income to determine its poverty status, see “How the Census Bureau Measures Poverty” on the Census Bureau’s web site.