To validate the University of Michigan Global Rating Scale (GRS), a single-item, five-point global measure of faculty members' clinical teaching performances previously shown to be reliable. In June 1998, 98 senior medical residents (98% of seniors) from four academic institutions completed the GRS for all teaching faculty at their institutions. Each resident also completed the 26-item Stanford Faculty Development questionnaire (SFDP26) for ten faculty with whom he or she had had teaching contact during residency. The SFDP26 is a validated instrument that measures seven specific aspects of clinical teaching (e.g., communication of goals, feedback). The mean GRS score (SE) was 3.83 (.07). There was no difference in mean GRS or SFDP26 subscale scores across institutions. In a random-effects model that controlled for interrater reliability, correlation coefficients comparing the mean GRS scores and the mean scores for the individual SFDP26 subscales ranged from.86 to.98. The GRS correlates highly with measures of seven specific aspects of teaching effectiveness among senior medical residents. The GRS is a simple, readily administered measure of faculty's teaching performances that can be used by residency programs as part of an incentive or reward program, to identify teachers as potential candidates for faculty development, or for consideration in promotion decisions.