This executive summary describes the larger study, "Teacher Preparation Experiences and Early Teaching Effectiveness. NCEE 2019-4007" (ED598664). This study provides information about new teachers' preparation experiences and explores whether particular types of experiences are related to teachers' effectiveness in improving their students' test scores. Understanding whether certain ways of preparing teachers are more effective than others is important, but very little is currently known about what teacher preparation emphasizes at a fine-grained level and how those experiences are related to teaching effectiveness. Research identifying which preparation experiences are related to improved student performance can generate hypotheses for improving teacher preparation. Through an online survey administered in spring 2015, this study collected information from new teachers about their preparation experiences. It also examined the relationship between the frequency of these experiences and teachers' effectiveness in improving student test scores. The summary describes how the study was conducted, key findings, and concluding thoughts.