The "Education and Career Planning in High School: A National Study of School and Student Characteristics and College-Going Behaviors" study examined the relationships between students' participation in three core elements of education and career planning during high school and their application, course-taking, and enrollment behaviors associated with the transition to college. The study sought to measure the self-reported education and career planning experiences of students enrolled in public schools and used student and counselor survey responses from a nationally representative longitudinal dataset. This document presents the following three appendixes that accompany the study: (1) Sample, data source, and analysis methods; (2) Handling of missing data; and (3) Supporting analyses. [For the full report, see ED615855. For the Study Snapshot, see ED615857.]