Why is the census important?

The census is important because it determines how many seats each state gets in the U.S. House of Representatives, how electoral votes are allocated, and how more than 1.5 trillion dollars per year in federal funding is distributed to states and localities. The Constitution requires the census in Article I, Section 2 specifically for the purpose of apportioning House seats among the states based on population. Every ten years, the 435 House seats are reallocated. Population gains relative to other states translate into added House seats; relative declines mean lost seats. The 2020 reapportionment added two seats for Texas and one seat each for Colorado, Florida, Montana, North Carolina, and Oregon. California, Illinois, Michigan, New York, Ohio, Pennsylvania, and West Virginia each lost one.

Within each state, congressional district boundaries must then be redrawn to reflect the new number of seats and population shifts within the state. Because each state's number of electoral votes equals its number of representatives plus its two senators, census results also reshape the Electoral College for the next decade. States that gain House seats also gain electoral votes. The 2020 census changes affected the 2024 presidential election, the 2028 election, and the 2032 election before the next reapportionment based on the 2030 census.

The federal government uses census data to allocate more than 1.5 trillion dollars per year through hundreds of federal programs. Major programs that distribute funds based partly on census data include Medicaid (joint federal-state health insurance for low-income Americans), Medicare (federal health insurance for older Americans), the Supplemental Nutrition Assistance Program (food stamps), the Special Supplemental Nutrition Program for Women, Infants and Children (WIC), federal highway funds, federal education funds including Title I for low-income school districts, special education funds, public housing funds, and many others. States that are undercounted in the census receive less federal funding for the next decade.

State and local governments use census data for planning roads, schools, hospitals, social services, and emergency response. Businesses use census data for market research, deciding where to locate stores, and product planning. Researchers, journalists, and policy analysts use census data for academic studies, news reporting, and policy evaluation.

The census is one of the largest peacetime mobilizations of the federal government, with hundreds of thousands of temporary workers hired to conduct each decennial count. The accuracy of the count has significant implications for the next decade.