||What kind of social control is generated by a particular form of power? How do the structural conditions under which this power is exercised determine high or low effectiveness? The first question is dealt with by distinguishing attitudinal conformity from behavioral conformity using the Merton dichotomy. The second inquiry utilizes the organizational characteristics of visibility of role performance vis á vis superiors, and the professionalism of staff personnel. The five power bases suggested by French and Raven--Coercive, Reward, Expert, Legitimate, and Referent--are specified and further developed. A hypothetical ranking of power bases predicts high correlations between behavioral conformity, high visibility, and Coercive power; relationships diminish down the ranking to high correlations between attitudinal conformity, low visibility, and Referent power. Data collected from 528 staff members in 18 city elementary schools are used for secondary analysis as a preliminary test of hypotheses.