Purpose. The purpose of this study was to determine if there was a significant difference in academic achievement on the California Standards Tests (CSTs) in English and mathematics of students enrolled in the California Partnership Academy compared to the nonacademy population. A second purpose was to analyze the percentage of first-time passage rate on the CAHSEE and determine if there is a significant difference and determine if there were significant differences in the Grade Point Average (GPA) of the same cohort of students in the study. Methodology. The sample size for the California Partnership Academy was 198 students who attended the CPA in tenth and eleventh grade, and a representative sample not enrolled in the academies. Random stratified sampling provided six samples, three different achievement groups from the academy classes and three from the general population. Findings. Academies helped increase CST ELA scores as students entered the academies in the tenth grade for high-achieving students; this was not evident among the medium- and low-achieving students in the academies. The academies did not have a significant impact on academy students in the tenth to the eleventh grade. The academies did not have a significant difference on high- and low-performing students who passed the CAHSEE ELA on the first attempt, and they did not show a significant difference among high- and low-performing students who passed the CAHSEE math. The academies indicated that the GPA for academy students from ninth to tenth grade increased. Conclusions. Higher-achieving students would have continued to achieve since they were achieving in the ninth grade and would continue achievement through the eleventh grade, but the data do not support this. The medium- and low-performing students showed no significant achievement after two years in the academy. The academies do not increase the first-time passage rate for the majority of the students in the academies. Recommendations. Compare similar academic achievement levels among academy and nonacademy students over a greater length of time (longitudinal study). It is also recommended that the study be replicated with a greater number of academy and nonacademy students with similar academic achievement levels. [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://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]