ACT maintains that monitoring academic strengths and weaknesses through the effective use of results from standardized tests can promote learning and intellectual growth. When schools use achievement test scores to guide curriculum choices and to provide feedback to students, opportunities for learning increase. The ACT Educational Planning and Assessment System (EPAS[R]) consists of three testing programs: EXPLORE[R] for eighth and ninth grades, PLAN[R] for tenth grade, and the ACT[R] test for eleventh and twelfth grades. When used together, the three EPAS tests function as an interrelated sequence of instruments for monitoring students' educational development throughout their high school careers. This study examined the scores of students who participated in all three of the EPAS testing programs and who attended schools identified as making effective use of EPAS. Criteria for effective are stringent, including discussion of scores with students and parents, use of student achievement data to inform curriculum decisions, and incorporation of the ACT College Readiness Standards[TM] into teaching plans. Findings indicate that initially lower-scoring students attending schools with effective EPAS use experience greater-than-expected academic growth. This is true for both genders and all racial/ethnic groups. Growth is most pronounced between eighth and tenth grades, when students who perform well begin to establish themselves on the path to college and workforce training readiness. The report concludes that schools that use EPAS effectively are likely to help those students who need help most. (Contains 2 figures.)