This appendix accompanies "Gaining Ground in the Middle Grades: Why Some Schools Do Better. A Large-Scale Study of Middle Grades Practices and Student Outcomes. Initial Research Report." This appendix focuses on the findings and domain comparisons of the study. This appendix contains the following: (1) Decision Rules; (2) Full Set of Subdomain Findings with Survey Items Reported in Initial Research Report; and (3) Statistical Comparisons across Study Domains. (Contains 4 figures.) [For the main report, see ED508673. For Appendix B, see ED508678.]