This book covers several dimensions of the undercount of young children in the U.S. Decennial Census, examines the data from the 2010 U.S. Decennial Census in detail and looks at trends in the undercount of children over time. Other aspects included are the geographic distribution of the net undercount and an exploration for some of the potential explanations for the high net undercount of children. The number of young children in the US is growing, but almost one million young children (under age 5) were missed in the 2010 U.S. Decennial Census. The net undercount of young children has been higher than any other age group for the past several decades and is increasing rapidly, but little attention has been paid to the issue but demographers or the public.

This open access book describes the differences in US census coverage, also referred to as "differential undercount", by showing which groups have the highest net undercounts and which groups have the greatest undercount differentials, and discusses why such undercounts occur. In addition to focusing on measuring census coverage for several demographic characteristics, including age, gender, race, Hispanic origin status, and tenure, it also considers several of the main hard-to-count populations, such as immigrants, the homeless, the LBGT community, children in foster care, and the disabled. However, given the dearth of accurate undercount data for these groups, they are covered less comprehensively than those demographic groups for which there is reliable undercount data from the Census Bureau. This book is of interest to demographers, statisticians, survey methodologists, and all those interested in census coverage.