State-Level 2010 Census Coverage Rates for Young Children

The Census Bureau’s demographic analysis (DA) shows that the net undercount rate for children aged 0–4 was 4.6 percent in the 2010 U.S. Decennial Census while adults (age 18 and older) had a net overcount rate of 0.7 percent. For the population aged 0–4, DA estimates are seen as more accurate than the U.S. Decennial Census because the estimates for this young population rely heavily on highly accurate birth certificate data. Given the relatively high net undercount rate for young children, it would be useful to examine census coverage rates for this population in subnational geographic units. In this study, the 2010 U.S. Decennial Census counts of children aged 0–4 are compared to the corresponding figures from the Census Bureau’s Vintage 2010 Population Estimates in each state. Differences between the 2010 U.S. Decennial Census count and the Vintage 2010 Population Estimates for the population aged 0–4 range from an estimated net undercount of 10.2 percent in Arizona to an estimated net overcount of 2.1 percent in North Dakota. Larger states tended to have higher net undercounts than smaller states. The ten largest states account for about 70 percent of the national net undercount of the population aged 0–4. Of all the factors examined here, the relative size of the Blacks Alone or in Combination plus Hispanics population is most highly correlated with the estimated net undercount of the population aged 0–4. Other measures that were highly correlated with net undercount rates for the population aged 0–4 were linguistic isolation, percent of adults without a high school degree, and the unemployment rate. In general, characteristics of people are more highly correlated with the net undercount rates of young children than the characteristics of housing units.