Although continuing medical education (CME) has long been used to inform physicians and teach specific skills, its efficacy in many areas is not well established. This randomized controlled trial assessed the effects of differing educational techniques on the cancer-control skills of 57 physicians.The CME program was part of the Cancer Prevention in Community Practice Project in Hanover, New Hampshire, and was implemented in 1988. The program used several methods in its presentation, including interactive small-group discussion, role playing, videotaped clinical encounters, lecture presentations, and trigger tapes. Measurements included cross-sectional observations made by unannounced standardized patients (SPs) who, one year after the CME program, assessed 25 physicians who had participated in the program and 32 physicians who had not. To measure consistency in the SPs' performances and accuracy in assessing the physicians' performances, most interactions were audiotaped using a hidden microphone. Pearson chi-square, Fisher exact two-tailed test, and kappa coefficients were used for analysis.Significantly higher ratings were found for the CME physicians in two areas: breast cancer risk-factor determination (determined maternal history: 80% versus 52%, p = .03; determined age at first period: 16% versus 0%, p = .02), and smoking cessation counseling (providing written material: 32% versus 9%, p = .03). The CME physicians were rated higher on all 19 study variables in the target areas of early detection of breast cancer and smoking cessation. The results show that the physicians' performance were better in those areas where the CME program had used performance-based learning, such as role playing or viewing and discussing a videotaped role-play encounter.The educational techniques that rehearsed or portrayed clinical applications seem to have increased the physicians' performances of cancer-control clinical activities. The standardized-patient instrument seems to be particularly useful in evaluating interventions that address specific skills training.