This study examined the effectiveness of teachers trained in a Professional Development School (PDS) versus a traditional program. The paper begins with data from earlier research which shows that PDSs prepare graduates better for teaching and managing classrooms than do traditional programs. This study used the North Carolina Teacher Performance Appraisal Instrument to evaluate teachers in their first 3 years of teaching. Teachers trained in a traditional program and teachers trained in a PDS program completed the evaluation. The instrument examined eight functions, though this study investigated only management of student behavior. Findings for years 1-3 showed that PDS teachers had better student behavior management scores in all measured areas than did teachers trained in a traditional program. The best, mediocre, and poorest PDS teachers were better than the best, mediocre, and poorest non-PDS teachers. One of the practices that positively impacted the level of classroom management performance was the formative, coaching nature of the evaluation process. Interns had regular opportunities to participate in non-threatening discussions of their teaching practice. Another positive practice for PDS students was their witnessing and participating in daily reflections with their cooperating teachers and other professionals. (SM)