The purpose of this research was to apply specific organization development strategies in a professional school to test the applicability of Argyris' Theory and Method Model for this setting. The research was designed to determine the effectiveness of group decision-making processes before and after intervention. In order to accomplish this, the research included two phases. The purpose of Phase One was to involve all members in the organization development program so valid information could be collected about strengths, limitations, and problems of the organization. Data for this phase were collected by individual and group interviews. These interviews, while unstructured, were designed to accomplish four objectives: (1)to provide information about perceived strengths and limitations, (2)to ascertain the direction participants wanted the organization to take, (3)to identify specific problem areas, and (4)to ascertain the perceived need for change. In addition, participants were asked to complete a questionnaire designed to elicit perceptions of emphasis given to four missions of the school and the adequacy of the support services and personnel. As a result of the data collected, a new organizational structure was developed by the participants and the researcher. Problem areas were also identified. Phase Two of the research was an experimental study of impact of three interventions on the effectiveness of a group. Effectiveness was measured by a positive change in (1)the degree of collaboration used in problem solving, (2)the effectiveness of communication, (3)role clarity, and (4)the level of trust, concern, and individuality behaviors. The two larger departments were selected for this phase, one serving as the experimental group and the other as the control group. Two data collection methods were employed, the Meetings Questionnaire and nonparticipant observation. The Meetings Questionnaire, a 36-item instrument, measures perceived collaboration, communication, and role clarity. Participants were asked to complete this questionnaire before and after intervention. Nonparticipant observation data were collected by trained observers using Argyris' system of categories. Baseline information on the percent of trust, individuality, and concern behaviors were collected for three weeks before intervention. Post-intervention data were collected for three weeks by the same observers. The organization development strategies employed in the three-week intervention period were surveyed feedback, process consultation, and coaching/modeling. In the survey feedback, data collected from both the questionnaire and the observations were reported to the experimental group during the first week at a two-hour department meeting. The observational categories were also explained and discussed. During the next two weeks, the researcher served as process consultant at the experimental group department meetings, using coaching and modeling of facilitative behaviors as a teaching method. Post-treatment data indicated no significant change in collaboration, communication, role clarity, or trust, concern, and individuality behaviors. The conclusions drawn were that the organization development strategies had little impact on improving organizational effectiveness. The fact that none of the hypotheses were supported does not mean that OD has no value for professional schools, but may be due to the inadequacy of the instruments used. It was further suggested that the time actually spent on intervention may have been too short and the intervention too mild to effect a change in the numerous dependent variables of the research.