This paper presents the research and methodology and analyses used for the "Gaining Ground in the Middle Grades" research. This appendix contains the following sections: (1) Overview; (2) Constructing the Survey Data File; (3) Constructing Composite Independent Variables (Subdomains); (4) Constructing Longitudinal Outcome Variables; (5) Constructing Data Files for Analysis; (6) Specifying Predictor Pools; (7) Regression Analyses; and (8) Statistical Comparisons across Study Domains. (Contains 4 figures and 6 footnotes.) [This report 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." For the main report, see ED508673.]