Predicting incoming enrollment is an ongoing concern for the School District of Philadelphia (SDP) and similar districts with school choice systems, substantial student mobility, or both. Inaccurate predictions can disrupt learning as districts adjust to enrollment fluctuations by reshuffling teachers and students well into the fall semester. The "Predicting Early Fall Student Enrollment in the School District of Philadelphia" study compared the accuracy of four statistical techniques for predicting fall enrollment at the school-by-grade level, using data from prior years, to assess which approach might be the most useful for planning school staffing in SDP. This document presents the following two appendixes that accompany the study: (1) Methodology; and (2) Supporting analyses. [For the full report, see ED615006. For the Study Snapshot, see ED615007.]