Reform legislation enacted by the 1983 General Assembly in Missouri prompted the development of guidelines for Performance Based Teacher Evaluation (PBTE) in order to improve education. This paper presents a study that examined principals' use of PBTE. For the research, 180 principals from elementary-school, middle-school, and secondary-school populations, ranging in size from 100 to 1,199 students, were surveyed. The survey questions explored traditional versus constructivist views of learning and thinking, and examined teachers and principals in a supervisory relationship. The survey asked such questions as, Is the PBTE process or a variation of that process in general use? and Are principals generally supportive of the "official" PBTE process? A total of 81 returned surveys were usable. Results were grouped by school size--100-299, 300-599, 600-1,199--and by school level. The respondents were primarily male (72 percent) and had used the PBTE process as a principal for 2 or more years. The principals demonstrated widespread support for several constructivist beliefs about teaching and learning. It seems likely that observation of teachers by principals may have achieved representative rule status and that this is a major accomplishment of the reform era. It is recommended that the current PBTE process be phased out. (RJM)