To promote the well-informed and strategic use of data for building the knowledge base about Latinos' ECE access and utilization, the interrelated briefs in this series provide summary information and data tables that can be used by researchers to select the studies, samples, and variables most appropriate for their research questions. This is the first of four briefs in this series. It describes the project methodology and summarizes key design features of the selected data sets, including the availability of sociodemographic indicators of particular relevance to studying Hispanic populations. (author abstract)