A product of Project Measurement, this facilitator's manual is designed for an inservice course on the use of measurement in the instructional process for special educators of mentally handicapped students. Project Measurement had three goals: (1) to provide a better measurement system for special education teachers, (2) to encourage a team approach to data collection, and (3) to provide consistent follow-up for inservice participants. The first section of the manual discusses the philosophy of formative or process-based evaluation and how it differs from the permanent product assessment more typically used in special education assessment. The next section provides a philosophy of decision making that relies on the ABMC model where A stands for antecedent conditions and interventions; B represents the behaviors being measured; M stands for the measurement component; and C indicates consequation interventions designed to enhance or eliminate the behavior in question. The third section contains material on basic measurement components including pinpointing, recording, and charting with an emphasis on precision teaching resources. The last section discusses decision making guidelines that significantly enhance the utilization of data collected so that process information directs instructional decision making. The appendix includes a complete set of overhead masters (also included in each section). (DB)