This study aimed at predicting the magnitudes of work efforts people expend to fit their work situations. The unit of inquiry was the dyadic working relationships between supervisors and subordinates, where the supervisors represent significant situations sending work roles to the subordinates. An objective measure assessing the level of the subordinates' work efforts was constructed using the ratings of their immediate supervisors, and it was predicted from such self-regulatory factors as self-efficacy, outcome expectation (incentive to work), ability conception, etc. The data indicated that those subordinates who were highly self-efficacious, perceived positive incentives to fulfill their work roles, and believed that ability can be improved through hard work, exerted greater efforts to attain a better fit with their task requirements. The findings are very similar to those obtained in the past research where effort has been operationalized using self-report measures. The meanings of the findings and directions for future research are discussed.