The Census Bureau uses poverty levels for whatever year the ACS survey was taken are used. The Census Bureau uses income thresholds to determine who is in poverty. If a family's total income is less than the family's threshold, then that family and every individual in it is considered in poverty. The official poverty thresholds do not vary geographically, but they are updated annually for inflation using the Consumer Price Index (CPI). The monthly inflation factor is based on 12 monthly Consumer Indexes and the base-year CPI (1982-1894=100). Then the data are aggregated to determine the five-year estimate.
