What are the differences between the poverty guidelines and the poverty thresholds?

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 1980 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 (301)763-2422.  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).

Key differences between the poverty thresholds and the poverty guidelines are summarized in the table below.  For more information, see the discussion of poverty thresholds and poverty guidelines on the Institute for Research on Poverty’s web site.

Key Differences Between Thresholds and Guidelines
	Poverty Thresholds	Poverty Guidelines
Issuing Agency	Census Bureau	Department of Health and Human Services
Purpose/Use	Statistical — calculating the number of people in poverty	Administrative — determining financial eligibility for certain programs
Characteristics by Which They Vary	Detailed (48-cell) matrix of thresholds varies by family size, number of children, and, for 1- & 2-person units, whether or not elderly.  Weighted average thresholds vary by family size and, for 1- & 2-person units, whether or not elderly.  There is no geographic variation; the same figures are used for all 50 states and D.C.	Guidelines vary by family size.  In addition, there is one set of figures for the 48 contiguous states and D.C.;  one set for Alaska;  and one set for Hawaii.
Timing of Annual Update	The Census Bureau issues preliminary poverty thresholds in January, and final poverty thresholds in August of the year after the year for which poverty is measured.  The poverty thresholds are adjusted to the price level of the year for which poverty is measured.  For example, the poverty thresholds for calendar year 2002 were issued in 2003 (preliminary in January, final in September), were used to measure poverty for calendar year 2002, and reflect the price level of calendar year 2002.	HHS issues poverty guidelines in February of each year. Some programs make them effective on date of publication, others at a later date.  For example, the 2003 poverty guidelines were issued in February 2003, calculated from the calendar year 2001 thresholds issued in September 2002, updated to reflect the price level of calendar year 2002.  Therefore the 2003 poverty guidelines are approximately equal to the poverty thresholds for 2002 (for most family sizes).
How Updated or Calculated	The 48-cell matrix is updated each year from the 1978 threshold matrix using the CPI-U.  The preliminary weighted average thresholds are updated from the previous year’s final weighted average thresholds using the CPI-U.  The final weighted average thresholds are calculated from the current year’s 48-cell matrix using family weighting figures from the Current Population Survey’s Annual Social and Economic Supplement.	Guidelines are updated from the latest published (final) weighted average poverty thresholds using the CPI-U.  (Figures are rounded, and differences between adjacent-family-size figures are equalized.)
Rounding	Rounded to the nearest dollar	Rounded to various multiples of $10 — may end only in zero

Source: U. S. Department of Health and Human Services

http://aspe.hhs.gov/poverty/faq.shtml#differences