The Evaluation of the Comprehensive Technical Assistance Centers 2015 (CTAC Evalution 2015) is a study of the Evaluation of the Comprehensive Technical Assistance Centers (CTAC Evaluation) program. CTAC Evaluation 2015 (https://ies.ed.gov/ncee/projects/evaluation/other_techcenters12.asp) includes cross-sectional surveys, cross-sectional interviews, and ratings of Center products that are designed to examine the Comprehensive Technical Assistance Centers (CTAC) program, a Federally funded program that provides technical assistance to states in connection with the No Child Left Behind Act (NCLB). Specifically, the study examines Center objectives and activities and assesses the quality of Center products. The study was conducted using surveys and interviews of State Education Agencies (SEAs), project participants, and Center staff. The study includes a sample of Center projects for review, a sample of technical assistance recipients (response rate of 80%), and comprehensive center staff (response rate of 100%). Key statistics produced from CTAC Evaluation 2015 are about the quality, relevance, and usefulness of Center projects and descriptive statistics about Center operations.