This chapter assesses recent progress in the social sciences regarding the conceptualization and measurement of neighborhoods as environments of human development. It reviews the literature on archival-based assessments of neighborhoods (e.g., various measures of census-based units). The systematic social observation approach provides data regarding the current physical state of neighborhoods, which is only indirectly inferred from census data. The chapter compares and contrasts these measures with subjective respondent-based indices (e.g., interviews, questionnaires, ethnographies) as well as observer-based methods. It highlights the strengths and weaknesses of each type of data. This chapter reviews newer methods for assessing neighborhoods such as geographical information systems (GIS) and spatial mapping approaches and policy-based experimental studies of neighborhood relocation. It addresses a variety of remaining problems in the measurement of these contexts. Finally, the chapter presents the policy implications of recent work on measurement of neighborhoods.