O’Hare, William P., Differential Undercounts in the U.S. Census: Who is Missed?. Springer Nature, 2019. https://library.oapen.org/bitstream/id/844a03c4-b79d-4b2e-93fe-2267f284daef/1007071.pdf.

As the topic of social injustice becomes more prominent in academic and community discussions, the general public and researchers may be interested in learning about the relationship between data accuracy in census surveys and social inequality in the United States. This book is a compilation of statistics and data discussing why certain groups of people have historically been uncounted and omitted in the decennial census. The decennial census is a count conducted every ten years of every person living in the United States in order to allocate federal funding to states for social services, determine state and congressional legislative districts, and the number of US House of Representatives for each state. William O’Hare gathers available information regarding undercounts and omission rates in the decennial census and summarizes the data to make it understandable for a general audience, as often this data is buried within census reports and presentations. In addition, O’Hare provides references to the data and methodology.

This book is freely available through an open access Creative Commons license and most of the statistics and data presented in the book are freely available through the Census Bureau. The intended audience are practitioners and advocates, such as civil rights organizations like the National Association for the Advancement of Colored People (NAACP) and the Mexican-American Legal Defense and Education Fund.

O’Hare begins with a background on the Census Bureau and the definitions of the concepts of omissions and undercounts in the decennial census. Then the author describes the importance of the accuracy in census surveys, as the data is used by businesses, policy and planning, and redistricting. O’Hare further outlines how the Census Bureau measures the accuracy of the decennial census and offers detailed references to explore the methods used by the Census Bureau to determine net undercount and omission rates. The subsequent chapters review the characteristics of groups that are traditionally undercounted by race and ethnicity, by sex, age, and tenure (renters or homeowners). In particular, the author summarizes that the following populations are undercounted: young children who are ages zero to four; renters; and race and ethnic groups that are black, Hispanic, and American Indian. The organization of the book is one of its strength, as each chapter focuses on a particular characteristic and makes it convenient for readers to find relevant information to their interests.

Next, O’Hare details possible explanations as to why certain groups may be missed in the data collection. Some reasons stated by the author were people living in complex or untraditional housing, such as a garage or basement converted into a separate household unit; confusion on who is included in the census, such as a misconceived perception that young children are not supposed to be included in the census; and people wanting to conceal themselves from the government for fear of negative outcomes, especially in the immigrant community. One example of missing data is when O’Hare states that prior to 1990, Hispanics were not systematically identified in birth and death certificates in all fifty states. Hence, only undercount estimates for Hispanics under twenty years old are available for the 2010 census. Another important point was that the Census Bureau treats the Hispanic population as a homogeneous group. However, the subgroups within the Hispanic population, like Mexican, Puerto Ricans, Central American, etc., are distinct in immigration and citizen statuses and have diverse social, economic, and cultural characteristics. Finally, O’Hare ends by examining the issues, such as underfunding and mistrust of the government, surrounding the 2020 census.

One strength of this book is at the end of each chapter there is a useful list of references for readers to conduct further research into the topics described in the book. O’Hare’s work is useful for researchers or non-academics interested in why certain populations are not counted accurately and to advocate for these groups in the next decennial census. Many librarians participated in disseminating accurate information for the 2020 census. As a result, we may already recognize the populations of people who have been traditionally undercounted in our local areas. However, this book goes deeper into technical and historical explanations surrounding the reasons why these groups are undercounted. Conducting a nationwide survey is a difficult endeavor but learning about the process of data collection and recognizing how and why some groups are not counted is a great step for anyone interested in understanding the inequality of services and representation for marginalized populations in the United States.—Eimmy Solis (eimmysol@usc.edu), Social Sciences Data Librarian, University of Southern California Libraries.