An administrator's daily life is full of decisions that often involve an "on the spot" solution. This paper discusses some of the principles involved in drawing inferences in research and decision making, and describes how a knowledge of decision-making errors can help administrators. The paper also describes a case study that illustrates common judgment errors that were made during one junior high school's transition to a middle school. The district superintendent had decided to change the school philosophy and practice to one consistent with the interdisciplinary teacher teams outlined in "Caught in the Middle." The paper describes the inferences and decision-making processes through which faculty and staff created a common preparatory period for all teacher teams. (LMI)