A longitudinal evaluation study of a science professional development program for K-12 teachers was conducted using the CIPP evaluation model. Eleven years of program data were described and analyzed. Elementary teachers comprised 62% of the 384 participants, 17% of all participants were middle school teachers, and 13% of all participants were high school teachers. The program was focused on education reform initiatives as prescribed in the RFPs of each of three different funding agencies. Activities were congruent with the principles of adult, life-long and active learning. Program design was carefully planned and supported, and focused on content that was coherent with the state's science standards. The program duration was significant; it spread across two semesters and one summer, and incorporating over 180 hours of coursework. Participants worked in small groups, often coming from the same schools, throughout the program. The professional development program that was the subject of this evaluation study was informed by research findings on best practices and adhered to the research-based elements of effective professional development programs. Results indicated that the professional development model that was studied resulted in increased self-efficacy for the science teachers who participated in the program. Increases in self efficacy have been shown to positively affect student achievement. It is therefore reasonable to conclude that the program had a positive effect on student achievement through the teachers who participated in the professional development program. Additionally, this evaluation has demonstrated that the program and associated activities were designed to address national priorities in existence when each proposal was written. [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.]