Families in poverty are defined based on income thresholds that vary depending on family size and composition. If the total income for the family is below the threshold, every individual in the family is considered poor. The definition of poverty is set at the federal level and does not vary based on geographic location. This can lead to undercounting in high cost-of-living areas. The federal poverty line is used to determine eligibility for several government programs, like the Supplemental Nutrition Assistance Program (food stamps), Medicaid, and public housing. It is updated yearly to account for inflation based on the Consumer Price Index (CPI-U).