In recent decades, social work and other social science research disciplines have become increasingly reliant on large secondary data sets, which have increased in both number and accessibility. When starting a new research project, how does one determine whether to use a secondary data set? Which of the thousands available should be used? This invaluable and expertly written guide provides an in-depth introduction to 29 of the most widely used data sets in social work, such as the Early Childhood Longitudinal Study, the National Health and Nutrition Examination Survey, and the U.S. Census. This book also examines the years covered by these cross-sectional and longitudinal data sets, the units of analysis, and the sample sizes. Readers will learn where to find the data and the key variables contained within, and how to use them in SAS and Stata. Screen shots guide researchers through data sets in a step-by-step process: how to download the data, how to merge it with other data sets, and how to program it when necessary. Each section also profiles studies that have used the respective data sets, giving researchers a clear feel for the depth and range of questions that a given data source can be used to answer, like the use of government data to explore issues ranging from pathways out of poverty to the relationship between marital dissolution and womens health and well-being. Exceptionally well calibrated and filled with real-world examples, this pocket guide will give beginning and advanced researchers a comprehensive understanding of these data sets that they can use in their research on clinical, policy, and other types studies.