Techniques to manage scarce healthcare resources continue to evolve in response to changing, growing and competing demands. Yet there is no standard definition in the priority setting literature of what might constitute the desired impact or success of resource management activities.In this 2006–09 study, using action research methodology, we determined the impact of implementing a formal priority setting model, Program Budgeting and Marginal Analysis (PBMA), in a Canadian health authority. Qualitative data were collected through post year-1 (n = 12) and year-2 (n = 9) participant interviews, meeting observation and document review. Interviews were analyzed using a constant comparison technique to identify major themes.Impact can be defined as effects at three levels: system, group, and individual. System-level impact can be seen in the actual selection of priorities and resource re-allocation. In this case, participants prioritized a list of $760,000 worth of investment proposals and $38,000 of disinvestment proposals; however, there was no clear evidence as to whether financial resources were reallocated as a result. Group and individual impacts, less frequently reported in the literature, included changes in priority setting knowledge, attitudes and practice. PBMA impacts at these three levels were found to be interrelated.This work argues in favor of attempts to expand the definition of priority setting success by including both desired system-level outcomes like resource re-allocation and individual or group level impacts like changes to priority setting knowledge, attitudes and practice. These latter impacts are worth pursuing as they appear to be intrinsic to successful system-wide priority setting. A broader definition of PBMA impact may also suggest conceptualizing PBMA as both a priority setting approach and as a tool to develop individual and group priority setting knowledge and practice. These results should be of interest to researchers and decision makers using or considering a formal priority setting approach to manage scarce healthcare resources.