This technical supplement provides details on the survey methodology and results presented in the report "Developing Effective Principals: What Kind of Learning Matters?" The full report shows that principals' access to high-quality learning opportunities varies across states and by school poverty level. To draw these conclusions, the authors present findings from several related survey efforts through which they were able to compare principals' preparation and professional development experiences. The supplement provides background information on the three survey efforts brought together in the full report. It then discusses the methodology and samples for each survey effort and presents each survey's full results. [For the full report, see ED620192.]