This brief offers lessons learned from California State University teacher preparation programs engaged in using data to inform improvement efforts. The authors consider teacher preparation programs as systems that can undergo continuous, data-driven improvement through an improvement science approach. Teacher preparation programs typically have focused on outcomes data as measures of whether the program is achieving its goals. But other kinds of data can be important as well. In particular, this brief focuses on process measures that provide data on which underlying systems or processes within a program must change in order to achieve more desirable outcomes. The brief also outlines a set of process measures, examining how each measure could indicate both the quality of major processes and the reliability with which the processes occur as intended.