arenas. A clear conceptual framework is needed to guide appropriate data collection and analysis for measurement and to identify key assumptions of the underlying model. This part of the report is intended to provide that framework.

Chapter 2 briefly reviews biological and social concepts of race and adopts a social–cognitive definition in which race is based on observable physical features and associated characteristics that have acquired socially significant meaning. As such, social categorizations of race evolve over time and differ in different societies and contexts. The chapter presents background on the history and meaning of race in the United States and summarizes the federal government’s racial and ethnic categories for data collection. The discussion reviews the ambiguities that complicate the definition and measurement of race.

Chapter 3 provides a social science definition of racial discrimination with two components that correspond to legal concepts of disparate treatment discrimination and disparate impact discrimination. Each component goes beyond a strictly legal definition to include some individual behaviors and organizational processes that may not be unlawful but that have discriminatory effects; that is, they result in adverse consequences for racial groups. We explain why we focus in this report on racial discrimination against disadvantaged groups, and we provide evidence of racial disparities in outcomes across various social and economic domains. Racial disparities can occur for many reasons; their existence motivates our examination of social science methods that can help determine the role that race-based discrimination may play in those differences.

In Chapter 4, we provide theories or models of racial discrimination. To be able to measure racial discrimination of a particular kind, it is necessary to have a theory or model of how such discrimination might occur and what its effects might look like. The theory or model, in turn, specifies the data that are needed to test the theory, appropriate methods for analyzing the data, and the assumptions that the data and analysis must satisfy in order to support a finding of discrimination. Without such a theory, analysts may produce results that are hard to interpret and do not stand up to rigorous scrutiny. The chapter discusses four types of discrimination and the various mechanisms that may lead to such discrimination. It then discusses how these discriminatory behaviors and practices might operate within the domains of education, employment, housing, criminal justice, and health. Finally, the chapter briefly discusses concepts of cumulative discrimination across domains and over time.