To evaluate the effectiveness of Service Unit Management (SUM) in reducing costs, improving quality of care, saving professional nursing time, increasing personnel satisfaction, and setting a stage for further improvements, a national questionnaire survey identified the characteristics of SUM units, and compared the performance of a total of 55 units with and without SUM. Data collected from each unit included personnel costs, quality of care, patient work load, personnel satisfaction, organizational tension and management style, personnel acceptance of SUM, assignment of responsibility, and type of SUM organization. Evaluation by a multi-disciplinary research team, representing the disciplines of industrial engineering, organizational science, and social psychology, revealed that in general SUM was serving the purposes claimed. In addition, the activities which characterize a unit management program were grouped as logistic and clerical, patient support, and administrative activities. Other findings are provided for the focus of SUM, organizational structure, unit manager qualifications, and the change process. An activities list and additional readings are appended, and an annotated bibliography of current literature on SUM is included. (SB)