Abstract: Decision support strategies involving small groups of managerial decision makers have become increasingly common in recent years. Group model building is one example of this. Group model building involves using system dynamics tools with groups to enhance system thinking skills to encourage productive problem solving. An important precondition to successful outcomes from group model building is alignment among participants around a shared understanding of the problem situation.; This dissertation examines the concept of alignment as a measurable phenomenon and assesses the degree to which it occurs among group model building participants. In addition, changes in alignment are compared with those of other individuals who do not participate. The research also examines comparative shifts in perception of problem importance and problem understanding.; The project was conducted in the context of a public policy decision making situation which focused on the integration of mental health and vocational rehabilitation services in New York State. The study design called for three comparative conditions consisting of two teams of policy makers form two counties. One condition received group model building only. The second condition received only an administrative mandate to address this policy initiative. The third condition received both an administrative mandate to address this policy initiative and group model building.; Data were collected pre- and post-intervention on group member characteristics, attitudes about the importance of integrating services, and perceptions of aspects of group process.; Overall, the study found that group model building made a positive difference in participants' perceptions of their alignment with their group members. Analyses of objective measures, however, failed to demonstrate significantly greater alignment for group model building participants. Group model building also made a positive difference in participants' perceptions of their understanding of the problem situation.; Implications for group model building researchers include the need for a better understanding of what group model building components made a difference and an identified need for clarifying alignment as a researchable construct. Implications involving alignment include the need for serious examination of its role in outcomes of system thinking interventions and consideration of ramifications for measurement and analytic approaches.