Estimating the Net Undercount of Young Children in the 2010 U.S. Decennial Census at the County Level

William O'Hare, Independent Consultant

Demographic Analysis (DA) shows there was a net undercount of 970,000 children age 0 to 4 in the 2010 Decennial Census which amount to 4.6 percent. It would be useful to examine how this net undercount of 970,000 people is distributed geographically. The 2010 Decennial Census country-level counts of children age 0 to 4 are compared to corresponding figures from the Census Bureau’s Vintage 2010 population estimates, to ascertain net overcounts and net undercounts. In the largest quintile of counties there was a collective net undercount of 6.0 percent for those age 0 to 4 and in the smallest quintile of counties there was a collective net overcount of 2.9 percent. National undercount rates for the population age 0 to 4 are driven largely by the results in large counties and do not reflect the experience in the “average” state or county.