Identifying, understanding, and addressing clinical variation is a useful tool to promote appropriate care while helping control health care costs. Although accurate, relevant, and useful data are important in the process, successfully engaging physicians to change behavior is often the most significant challenge. Using a commercially available variation analysis process, a California Medicaid managed care plan identified significant network practice pattern variation. A team of panel practitioners then developed a strategy to reduce overuse of 5 identified behaviors. The intervention was evaluated using a pre-post comparison of the panel's use of the 5 behaviors. During the preintervention period, narcotics, muscle relaxants, magnetic resonance imaging (MRI), and spinal injections increased between 8% and 18% per month. Postintervention, the trends reversed. The differences were statistically significant (P<.0001) for muscle relaxant use, narcotic use, overall MRI use, and spinal injections. Peer comparison data and respectful feedback was associated with significant change in patterns of overuse.