In evaluating its first year of the Student Progress Plan (SPP), the District of Columbia Public Schools found that more students were promoted under SPP than would have been promoted under the traditional policy. Implemented in grades 1-3 in 125 schools as part of the school district's competency-based curriculum, SPP is a skills mastery plan in which promotions or retentions are decided at the end of each semester instead of the end of each year, based on reading and mathematics scores on the California Test of Basic Skills. Students who master one skill but not the other are placed in transitional classes in the skill not yet mastered. The report compares rates of promotion by student educational need (indicated by Title I status under the Elementary and Secondary Education Act), reading and math achievement level, sex, and participation in Operation Rescue, a volunteer tutorial program. Results of the evaluation show that a higher proportion of all students and of Title I students were promoted at the end of the second semester than at the end of the first, and that more girls than boys were promoted. A final chapter reviews the research literature on sex differences in academic achievement. (Author/RW)