Research shows that effective teachers are one of the most important in-school contributors to student learning. To improve low-income minority students' access to effective teaching, the Bill & Melinda Gates Foundation launched the Intensive Partnerships for Effective Teaching (IP) initiative in the 2009-2010 school year. The program was implemented in three public school districts and four charter management organizations (CMOs) across the United States. Researchers examined a variety of outcomes, but analysis suggested that, overall, the initiative did not reach its goals. In particular, student achievement, low-income minority students' access to effective teachers, and dropout rates were not substantially better in the IP sites than in similar sites that did not participate in the initiative. Although this analysis of impact, which was published in 2018, did not find that the initiative was effective overall, the researchers did observe that some IP schools had improved more than others. The study team decided to dig deeper into the variation in outcomes among schools and look for school-level factors associated with that variation. Newly collected qualitative data, as well as new analyses of survey data from the original study, allowed the team to more closely investigate the factors that differed between the improving and nonimproving IP schools and develop recommendations for future variation studies of multisite efforts. [This brief describes work documented in "Improving Teaching Effectiveness: Variation in Improvement among Schools in the Intensive Partnerships for Effective Teaching." For this report, see ED609290.]