This study examines the effects of adoption of ACT® Aspire® Periodic Assessments on student academic growth, as measured by the ACT Aspire Summative Assessments. A difference-in-difference analysis shows that adoption of the ACT Aspire Interim Assessments leads to improvements in academic growth. Averaging results across all subject areas and grade levels, adoption typically led to an increase in student growth of 1.3 student growth percentile units, which is comparable to moving from the 50th percentile of school growth to the 56th percentile of school growth. The effect of adoption was strongest for English (+2.9 growth percentile units), followed by science (+1.4 growth percentile units) and math (+1.1 growth percentile units). For reading, effects of adoption were inconsistent across grade levels.