Title: Using Developmental Evaluation to Address Uncertainty from a Systems Perspective Abstract 3: This presentation will discuss how three developmental evaluations addressed issues of uncertainty. The studies took place in different settings: (1) a University-based public/private partnership seeking to transform health professions education and clinical practice nation-wide; (2) six organizations collaborating to address youth homelessness in a major urban center; and (3) a collaboration between a foundation and an urban school district. In each case---and unavoidably---the evaluators faced uncertainty in numerous areas (e.g., who were key actors and what contextual factors would support or constrain the evaluation process) and at different levels (program level, collaboration or cross-organization level, and policy level). The presentation will provide details of how specific uncertainties were addressed, i.e., what was the uncertainty, what processes were used to gather information and plan to address it, and what ultimately happened. The discussion will highlight specific useful features of developmental evaluation in addressing uncertainty. Jean King (kingx004@umn.edu), University of Minnesota Nora Murphy (nora@terralunacollaborative.com, 773-613-9622), Terraluna Collaborative#developmentalevaluation #Systems #Complexity