The contributions of assistant principals (APs) toward improving student and staff outcomes has not yet been a focus of much empirical research. In recent years, as the increased focus on improving student outcomes has shifted expectations and APs are now expected to perform some instructional leadership tasks, such as coaching and evaluating teachers. To date, there have been few studies of AP professional development programs, and little is known about the extent to which APs are trained to undertake instructional leadership activities. In the main report, "Pathways to Instructional Leadership: Implementation and Outcomes from a Job-Embedded School Leader Training Program," the authors present findings about implementation and impacts on staff and student outcomes from a four-year study of the Pathway to Leadership in Urban Schools (PLUS) program in a large, urban public school district. PLUS was developed by TNTP (formerly The New Teacher Project) to train APs in instructional leadership. The findings could help policymakers, district staff, and training program providers understand participants' perceptions of programs that focus on training APs in instructional leadership and the impact that such a program can have on student and staff outcomes. The findings could also help program providers and district staff understand some of the benefits and challenges associated with training school leaders in the context of district-provider partnerships. This technical appendix provides more detail about data, samples, methodology, and results from additional exploratory analyses conducted by the authors. [For the full report, see ED606236.]