RAND Corporation researchers performed a cross-case analysis, using a purposive sample of 10 Wallace grantee sites consisting of 10 states and their 17 affiliated districts. Before conducting site visits, they reviewed the literature on system-building and policy coherence and developed an understanding of the indicators of cohesive systems that they used to structure, compare, and interpret the findings. Researchers then conducted site visits during which they interviewed 300 representatives of districts, state government, and pre-service principal preparation programs. RAND also fielded a survey of more than 600 principals and collected information in an online log in which nearly 170 principals described how they spent their time every day for two weeks. They supplemented this information by interviewing 100 principals.