The Census Bureau acknowledges the long-standing undercount of young children in decennial censuses and in Census Bureau surveys. Evaluations show that Census Bureau surveys like the American Community Survey, the Current Population Survey, and the Survey of Income and Program Participation also undercount young children, which can result in biased survey estimates. The differential undercount of this population across geography and demographics makes this a larger problem for some racial and ethnic groups and some parts of the country. However, this issue is not unique to the United States, as research has shown that many other countries have a high net undercount of young children in their censuses.
In response to this pervasive issue, the Census Bureau has spent years researching children who were missed in the 2010 Census and taken many steps to attempt to reduce this undercount in the 2020 Census. This research, along with other relevant materials, is presented here.
U.S. Census Bureau "Working Papers" have not undergone the review and editorial process generally accorded official Census Bureau publications. These working papers are intended to make results of Census Bureau research available to others and to encourage discussion on a variety of topics.