Most training programs use learners' subjective ratings of their teachers as the primary measure of teaching effectiveness. In a recent study we found that preclinical medical students' ratings of classroom teachers were associated with perceived charisma and physical attractiveness of the teacher, but not intellect. Here we explored whether the relationship between these variables and teaching effectiveness ratings holds in the clinical setting. We asked 27 Internal Medicine residents to rate teaching effectiveness of ten teachers with whom they had worked on a clinical rotation, in addition to rating each teacher's "clinical skills," "physical attractiveness," and "charisma." We used linear regression to study the association between these explanatory variables and teaching effectiveness ratings. We found no association between rating of physical attractiveness and teaching effectiveness. Clinical skill and charisma were independently associated with rating of teaching effectiveness (regression coefficients [95% confidence interval] 0.73 [0.60, 0.85], p < 0.001 and 0.12 [0.01, 0.23], p = 0.03, respectively). The variables associated with effectiveness of classroom and clinical teachers differ, suggesting context specificity in teaching effectiveness ratings. Context specificity may be explained by differences in the exposure that learners have to teachers in the classroom versus clinical setting--so that raters in the clinical setting may base ratings upon observed behaviours rather than stereotype data. Alternatively, since subjective ratings of teaching effectiveness inevitably incorporate learners' context-specific needs, the attributes that make a teacher effective in one context may not meet the needs of learners in a different context.