Why Are So Many Young Children Undercounted in the U.S. Census?

Children under the age of 5 face the highest risk of being undercounted in the U.S. decennial census. In the 2010 Census, there was a net undercount of almost 1 million young children. PRB estimates that at least 4 million children live in areas with a very high risk of undercounting young children in the 2020 Census.

As households prepare to fill out their census forms, this primer explains why young children are missed and why it matters.

Why are so many young children missed in the U.S. census?

Children under the age of 5 are undercounted for several reasons, which can vary across different neighborhoods. Some adults may not realize that babies, toddlers, and young children are supposed to be included in the census and leave them off the census form. Children’s living arrangements also play an important role in child undercount. Young children who live in female-headed households or grandparent-headed households are at higher risk of being missed, as are those who live in blended families or multigenerational households. Also, children who split their time between multiple households—like those in joint custody arrangements—are at greater risk of being missed. PRB analysis suggests that two measures currently being used to identify areas where young children are more likely to be missed—the 2010 Census mail return rate and the Low Response Score (also based on mail return rates)—are not very good predictors of net undercount rates for young children in large counties. A 2020 PRB paper shows that young children are more likely to be missed in neighborhoods with high shares of:

  • Children under age 5 living in poverty.
  • Adults ages 18 to 34 without a high school diploma or GED.
  • Children living in female-headed households with no spouse present.
  • Children under age 6 living with grandparent householders.
  • Households that are limited-English speaking.
  • Children living in immigrant families.
  • People living in renter-occupied housing units.

How long has the undercount of young children been an issue?

The undercount of young children is not a new issue. Demographers have found evidence of undercounts as far back as the 1880 Census. However, since 1980, the net undercount rate for young children in the U.S. decennial census has been increasing while the rate for adults has been falling. If unchecked, the undercount rate of young children may continue to climb.

What is the potential impact of undercounting young children?

Census data are used to allocate federal funding for programs such as Head Start and the Supplemental Nutrition Assistance Program (SNAP) and guide policy planning by states and local jurisdictions. When young children are missed, communities do not get their fair share of federal resources, and local policymakers do not have accurate information to develop long-term plans for schools and other services.

What can be done to address the undercount of young children?

Community organizations and others need new tools to better pinpoint neighborhoods that require special outreach and attention during the decennial census. The Count All Kids initiative has resources that advocates can use for outreach, including links to a PRB database and an interactive map (developed by the CUNY Mapping Service at the City University of New York’s Graduate Center) that show the risk of undercounting young children across census tracts in nearly 700 large U.S. counties.