In examining the topic of evaluation, it is necessary to look at the role of evaluation in supervision and professional development. For any program to be effective, research states that accountability must be the focus of those responsible for the program. Evaluation of program, results, and personnel is part of providing for accountability. The Performance-Based Professional School Counselor Evaluation System was designed and tailored for the role of the school counselor. School counselors, administrative personnel, and representatives from the Missouri School Counselor Association were just a few of the groups who helped design the evaluation tool. The instrument has the potential of bringing the activities of professional school counselors in line with their expertise and ensures students gain competency in necessary skills. The effectiveness of the evaluation is dependent upon mentoring new counselors and teachers in collaborative decision-making skills regarding the evaluation process. (JDM)