In Poverty in the United States: 2024, the U.S. Census Bureau released updated estimates of the official poverty measure and the Supplemental Poverty Measure (SPM). Using the 2024 and 2025 Current Population Survey, Annual Social and Economic Supplements (CPS ASEC), the report shows that while the official poverty rate fell by 0.4 percentage points in 2024 to 10.6%, the SPM rate was 12.9%, not statistically different from 2023. A primary reason for these results is the difference in how poverty thresholds—or the definition of basic need —are updated each year. To learn why the Census Bureau produces two different poverty rates (the official poverty measure and the SPM), check out our recently released blog. 

The official poverty measure has been produced since the 1960s and defines poverty by comparing pretax money income to a national poverty threshold that varies by family size and age of the householder. The poverty threshold was originally defined as three times the cost of a minimum food diet in 1963 and is annually adjusted for inflation using the Consumer Price Index for All Urban Consumers (CPI-U). The CPI-U is the headline inflation statistic produced monthly by the Bureau of Labor Statistics (BLS) and reflects consumer spending across a range of goods and services. Conceptually, the CPI-U is capturing a general sense of changes in cost of living over time.¹

First released in 2011, the SPM was developed after significant research and consideration following the 1995 National Academies of the Sciences panel on measuring poverty. The measure is produced in collaboration with BLS. The SPM defines poverty by comparing a wider definition of resources (including noncash government benefits, taxes and credits, and necessary expenses) to a threshold that is defined as 83% of the total spending of a median consumer unit on food, clothing, shelter, utilities, telephone, and internet (FCSUti). The thresholds are constructed for three housing tenure groups (owners with a mortgage, owners without a mortgage, and renters) and are adjusted for geographic variation in housing costs across the country. BLS produces SPM thresholds each year using information on FCSUti expenditures from five years of Consumer Expenditure Survey data, lagged by one year. To equalize the data across the five-year period, prior year expenditures are adjusted for inflation using a limited price index that includes only the FCSUti items.² As a result, year-to-year changes in the SPM thresholds reflect changes in a narrower definition of cost of living (through FCSUti inflation) and updated spending patterns on those items (through new data).

The year-to-year rates of change for the poverty thresholds are shown in Figure 1. From 2023 to 2024, SPM thresholds increased by 5.8% for owners with a mortgage, 5.6% for owners without a mortgage, and 5.2% for renters.^3,4 Meanwhile, the official poverty thresholds increased by 2.9%.⁵

One way to evaluate the impact of the annual threshold adjustments is to update the 2023 SPM poverty thresholds using the CPI-U inflation rate used for the official measure. This effectively “anchors” the SPM in the living standards of 2023 (defined as the consumption patterns of the SPM threshold sample for 2023) while updating thresholds for price changes between 2023 and 2024 (hereafter referred to as anchored SPM).

Figure 2 plots these estimates alongside the 2024 SPM rates as published in Poverty in the United States: 2024. The anchored SPM in 2024 was 12.4%, 0.6 percentage points lower than the published SPM estimate in 2024. Poverty rates using the anchored SPM are lower than the published SPM rates for all presented demographic and housing tenure groups. 

Figure 3 compares last year’s published SPM poverty estimates to the 2024 anchored SPM. This year-to-year comparison shows that poverty would have fallen by half a percentage point to 12.4% if only price adjustments using the CPI-U were considered in the construction of SPM thresholds. Unlike the results in the report, there were no statistically significant increases in poverty for the presented groups using the anchored SPM.

The difference between the 2023 SPM and 2024 anchored SPM was not statistically different from the year-to-year difference in the official poverty measure which declined 0.4 percentage points to 10.6%. In other words, year-to-year changes in poverty across the two measures were not statistically different when only price adjustments are considered.

After many years of research and consideration, the SPM was designed to capture changes in both standards of living and prices over time, rather than just changes in price levels like the official poverty measure. In most years, this conceptual difference is not consequential, as the annual adjustments to the SPM thresholds and the official poverty thresholds have typically not been statistically different. The last two years have been different, as the adjustments to SPM thresholds were greater than the official adjustments for some housing tenures. As a result, differences in poverty trends across the two measures are largely driven by how the thresholds are updated over time, rather than by the amount of resources families have.

More information on poverty estimates can be found in Poverty in the United States: 2024.

Definitions and information on confidentiality protection, sampling error, and nonsampling error are available at <https://www2.census.gov/programs-surveys/cps/techdocs/cpsmar25.pdf>. All comparative statements have undergone statistical testing and are statistically significant at the 90 percent confidence level unless otherwise noted. 

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