Poverty thresholds are used for calculating all official poverty population statistics — for instance, figures on the number of Americans in poverty each year. They are updated each year by the Census Bureau. Poverty thresholds since 1973 (and for selected earlier years) and weighted average poverty thresholds since 1959 are available on the Census Bureau’s web site.
For poverty thresholds before 1980, contact the Census Bureau at 1-800-923-8282. 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.
The poverty guidelines are a simplified version of the federal poverty thresholds used for administrative purposes — for instance, determining financial eligibility for certain federal programs. They are issued each year in the Federal Register by the Department of Health and Human Services (HHS).
To learn about the key differences between poverty thresholds and poverty guidelines, you may want to visit: http://aspe.hhs.gov/poverty/faq.shtml#differences