2020 Census Net Coverage Error, by age

The 2020 Census undercounted children (ages 0-17) but the largest undercount was young children. The 2020 Census missed one in 20 children ages 0-4.

Net coverage error by age groups, U.S.

Percent of under- and overcounts, 2020 Census

Source: Census Bureau: 2020 Demographic Analysis. Notes: “Middle series” estimates of net coverage error.

For many decades, the U.S. Census has undercounted children. The 2020 undercount of young children 0-4 years old was larger than any Census since 1970.¹ These undercounts reduce both political representation and funding for children nationwide. The reduction in funding is particularly concerning as census numbers serve as the base for updated annual estimates. These annual population estimates in turn determine the federal resources that will be provided for such areas as food, housing, education, and medical programs for each year until 2030. At least $1.5 trillion in federal funding is distributed each year based on these annual estimates.²

Efforts to mitigate these undercounts in the annual population estimates are under way at the Census Bureau. The Bureau adjusted the 2020 data (that serves as a base for the subsequent annual estimates) by incorporating counts of children based on birth certificates – thus mitigating the undercount of children at the national level. Next the Bureau will need to research methodologies for distributing the estimates of children accurately geographically. The Bureau has established the Base Evaluation and Research Team to determine how they can mitigate undercounts in the 2020 data used as the “base” for the annual population estimates.³ The Census Scientific Advisory Committee recommended that the Bureau increase resources to this effort to support a continuous year-round improvement effort throughout the decade.⁴

1. “Despite Efforts, Census Undercount of Young Children Persists”. Jensen. U.S. Census Bureau. March, 2022. https://www.census.gov/library/stories/2022/03/despite-efforts-census-undercount-of-young-children-persists.html 

2. “Key facts about the quality of the 2020 census”. Cohn, Passel. Pew Research Center. June, 2020. https://www.pewresearch.org/fact-tank/2022/06/08/key-facts-about-the-quality-of-the-2020-census/ 

3. “Briefing on the Base Evaluation and Research Team”. Hartley, Perry. U.S. Census Bureau. https://www2.census.gov/about/partners/cac/sac/meetings/2022-09/presentation-briefing-on-base-evaluation-and-research-team.pdf 

4. “Census Bureau Census Scientific Advisory Committee Recommendations from Fall 2022 Meeting”. September, 2022. https://www.documentcloud.org/documents/23116287-census-bureau-census-scientific-advisory-committee-recommendations-from-fall-2022-meeting