LXD Research conducted a third-party, mixed-methods efficacy study of 95 Percent Group's Phonics Core Program (95 PCP) to determine the program's impact on fourth and fifth grade students' literacy outcomes. Outcomes included Istation's Indicators of Progress (ISIP) Advanced Reading and the State of Texas Assessments of Readiness (STAAR). LXD Research also completed qualitative activities to hear directly from participating educators about the training and implementation of the Tier 1 curriculum through interviews, focus groups, and surveys. Results indicated that 95 PCP fourth and fifth graders significantly outperformed the comparison group in Spring 2024 ISIP overall scale scores. Additionally, both 95 PCP fourth and fifth graders showed significantly greater growth from BOY-EOY on ISIP than their comparison group peers. Fourth and fifth graders also significantly outperformed the comparison group on spring 2024 ISIP comprehension and fluency subdomains. On the STAAR assessment, 95 PCP Students in grades 4-5 combined had significantly greater Spring 2024 levels and Spring 2023-2024 growth in reading overall scale scores than the comparison group. Although both grade levels had greater growth than the comparison group, the significant findings in STAAR growth were primarily driven by grade 5 students, whereas the grade 4 STAAR differences were not statistically significant. The educator interviews provided insights regarding the "learning curve" of implementing a new program with new content in upper elementary grades. It took teachers time and practice to feel comfortable and confident implementing the explicit and systematic 95 PCP lessons for the first time; however, once the educators were comfortable implementing the program, they reported seeing a positive impact with their students' reading abilities. These educator interview responses, paired with significant quantitative findings in the quantitative assessments, indicate the efficacy of the 95 PCP program.