This study examined the longitudinal performance of a district-wide cohort of students who had accumulated scores for both kindergarten and first and second grade analysis. The sample was disaggregated by pre-kindergarten participation and student demographics such as gender, minority status, limited English proficiency, students with disabilities, and socioeconomic status. The KRI Language, KRI Math, SAT-10 Reading, and SAT-10 Math assessment scores were used for the data analysis. Sample data were collected from the beginning of kindergarten and at the end of second grade. This study utilized the average treatment effects (ATE) model in observational studies to determine the effects of the Voluntary Pre-kindergarten (VPK) education program on the achievement measures in an urban school district. The results of the univariate tests were somewhat mixed, revealing no difference in the comparison of means test for the academic achievement outcomes between VPK and non-VPK participants in the first grade but some difference in the second grade. The ATE results revealed some important patterns. First, the study found a positive and statistically significant relationship between kindergarten achievement scores and specific first-grade and second-grade reading and mathematics skills and knowledge. Second, students with minority and low-income status, who were male, and who had disabilities, were associated with a negative impact on reading and math achievement. The study also found higher academic achievement results for second-grade students who were enrolled in schools with high Tennessee Value-Added Assessment System (TVAAS) scores and optional-school programs. Third, on the whole, the academic effects of the VPK program in later grades were mixed, where the ATE results suggest negative effects in reading and math scores in the first grade and, in some cases, evidence of positive effects in reading scores in the second grade. .