For statistical purposes (e.g., counting the poor population), the United States Census Bureau uses a set of annual income levels, the poverty thresholds, slightly different from the federal poverty guidelines.
As with the poverty guidelines, they represent a federal government estimate of the point below which a household of a given size has pre-tax cash income insufficient to meet minimal food and other basic needs.
Poverty thresholds were originally developed in 1963–64, based largely on estimates of the minimal cost of food needs, to measure changes in the impoverished population.
The thresholds form the basis for calculating the poverty guidelines and, like them, are adjusted annually for overall inflation.
The same threshold is used throughout the United States and does not vary based on geographical location.