Social psychologists are persuaded that researchers as well as laymen tend to overestimate the influence of personal traits and underestimate the influence of situations on observed behavior. The author of this article suggests that education researchers and policy makers may be overestimating the role of personal qualities in their quest to understand teaching quality. In their effort to understand classroom-to-classroom differences in student learning, they may focus too much on the characteristics of teachers themselves, overlooking situational factors that may have a strong bearing on the quality of the teaching practices we see. The author reviews some of these situational forces.