This study of usage and effectiveness of Goalbook Toolkit is based on student data from a large suburban school district in the northeastern US and teacher-level application usage data from Goalbook Toolkit from the 2021-2022 school year. Goalbook Toolkit enables teachers to personalize instructional supports for specialized student populations. In the district, special education teachers or resource teachers that provide direct services to students through pull-out, push-in, or co-teaching have access to Goalbook Toolkit. They use the application to support the Individualized Education Program (IEP) development, progress monitoring, and specially-designed instruction in general. The main research question is whether use of Goalbook Toolkit has a positive impact on student achievement in reading. The report presents the findings from two studies for an in-depth exploration of Goalbook Toolkit's effect on student outcomes. The comparison group and correlational analyses use different samples and provide different tiers of evidence of impact.