The SEL Demonstration Initiative study was designed to support sites in building their capacity to deliver high quality SEL practices while simultaneously supporting the four networks to intentionally implement an SEL aligned continuous quality improvement system. Each network led a continuous quality improvement process, namely, the Youth Program Quality Intervention (YPQI), using an observation based measure of SEL staff practices, the SEL Youth Program Quality Assessment (SEL PQA), as well as youth SEL behavior measure based on staff observation, the Staff Rating of Youth Behavior (SRYB). Both data sets were collected at two points in time during the year. The SEL PQA included external assessment with a reliable rater as well as self-assessment, a peer observation method with scoring based on group consensus. Additionally, staff completed a survey and participated in focus groups and interviews to provide feedback on the experience. (author abstract)