The relationships between course work taken, educational needs and plans, high school attended, and PLAN test scores of high school sophomores were examined. The PLAN tests are higher-order thinking skills tests that are used in educational planning for individuals and in program and curriculum evaluation. The relationships between ethnicity of gender and test scores were then considered by statistically controlling for these factors. The data consisted of two samples: 7,000 sophomores from 65 high schools who were intended to represent sophomores nationwide and a sample of 8,441 sophomores from 73 PLAN user schools that tested all of their sophomores. The results showed that course work taken, students' educational needs and plans, and high school attended were major factors in explaining students' achievement of higher-order thinking skills. Gender and ethnicity explained 2% or less of the variance in PLAN scores, over and above these factors. Appendix A presents clusters for planned course work, and Appendix B presents descriptive statistics and correlations for independent variables in three tables. The text contains 11 tables of study data. (Contains 10 references.) (Author/SLD)