Objective To explore the extent to which commonly used claims‐based process quality indicators can be used to create an internally valid global composite measure of physician practice quality. Data Sources Health insurance claims data (October 2007–May 2010) from 134 physician practices in Seattle, WA. Study Design We use confirmatory and exploratory factor analysis to develop theory‐ and empirically driven internally valid composite measures based on 19 quality indicators. Data Collection Methods Health insurance claims data from nine insurance companies and self‐funded employers were collected and aggregated by third‐party organization. Principal Findings Our results did not support a single global measure using the entire set of quality indicators. We did identify an acceptable multidimensional model (RMSEA = 0.059; CFI = 0.934; TLI = 0.910). The four dimensions in our data were diabetes, depression, preventive care, and generic drug prescribing. Conclusions Our study demonstrates that commonly used process indicators can be used to create a small set of useful composite measures. However, the lack of an internally valid single unidimensional global measure has important implications for policy approaches meant to improve quality by rewarding “high‐quality physicians.”