As of 2021, eighteen states plus the District of Columbia have implemented legislation regarding mandatory test-based grade retention focusing on minimum reading proficiency levels (National Conference of State Legislatures, 2019) with many of those policies targeting the third-grade year. While grade retention has been largely viewed negatively in the research conducted prior to NCLB, some studies of the academic effects of other city- or state-wide test-based retention policies in recent years have found that there can be positive outcomes. Indiana is one of the states with a retention policy tied to IREAD-3, a reading test in Grade 3, but up to now, the effectiveness of this policy has not been studied thoroughly. The decision to retain a student in grade is complex and critical with a variety of factors to understand as well as meaningful and far-reaching consequences to consider. This study focuses on the academic effects of test-based retention on students in the 2012 Grade 3 cohort in Indiana and follows them through Grade 8 using ISTEP+ results. A comprehensive, statewide dataset is analyzed using descriptive and inferential statistical approaches, culminating with longitudinal multilevel modeling to control for many student-level factors as well as their school districts. Consistent with some of the similar studies conducted in other cities and states, this study finds that retention has a positive effect on academic performance in a same-grade comparison in both English / Language Arts and Mathematics. These findings support the idea that grade retention could be considered a viable intervention policy; however, it is important to consider the ancillary supports and efforts that often accompany retention policies and view the positive gains as an aggregate of these efforts. Considered as a part of the existing body of research on grade retention, there is still much to be understood about most appropriate uses of the practice of grade retention. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]