This quantitative research study investigates the relationship between teachers' evaluation rating and their classroom-based assessment practices using a survey approach. Four middle schools consisting of 39 (grades six through eight) teachers in the Southwestern U.S. participated in the study. Research has shown that when teachers regularly use a system of evidence-based classroom assessment practices, student achievement increases. The problem addressed within this investigation is that students nationwide are performing at lower proficiency rates in math and English Language Arts than previously seen. Results from this study indicate that even teachers rated "highly effective" on evaluations are not employing evidence-based assessment practices more frequently than their lower-rated peers. As a result, data analysis provides both rationale and steps for strengthening all teachers' classroom assessment systems through mastery learning-based professional development for school improvement and increased student success. [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.]