Moving beyond Aim Three: a need for a transdisciplinary approach to build capacity for economic evaluations in implementation science.

backgroundUnderstanding the costs and economic benefits of implementation has been identified by policymakers and researchers as critical to increase the uptake and sustainment of evidence-based practices, but this topic remains relatively understudied. Conducting team science with health economists has been proposed as a solution to increase economic evaluation in implementation science; however, these recommendations ignore the differences in goals and perspectives in these two fields. Our recent qualitative research identified that implementation researchers predominantly approach health economists to examine costs, whereas the majority of health economists expressed limited interest in conducting economic evaluations and a desire to be more integrated within implementation science initiatives. These interviews pointed to challenges in establishing fruitful partnerships when health economists are relegated to the "Third Aim" (i.e., lowest-priority research objective) in implementation science projects by their research partners. DISCUSSION: In this debate paper, we argue that implementation researchers and health economists need to focus on team science research principles to expand capacity to address pressing research questions that cut across the two fields. Specifically, we use the four-phase model of transdisciplinary research to outline the goals and processes needed to build capacity in this area (Hall et al., Transl Behav Med 2:415-30, 2012). The first phase focuses on the development of transdisciplinary research teams, including identifying appropriate partners (e.g., considering policy or public health researchers in addition to health economists) and building trust. The conceptual phase focuses on strategies to consider when developing joint research questions and methodology across fields. In the implementation phase, we outline the effective processes for conducting research projects, such as team learning. Finally, in the translation phase, we highlight how a transdisciplinary approach between health economists and implementation researchers can impact real-world practice and policy. The importance of investigating the economic impact of evidence-based practice implementation is widely recognized, but efforts have been limited due to the challenges in conducting team science across disciplines. Training in team science can help advance transdisciplinary efforts, which has the potential to increase the rigor and impact of economic evaluations in implementation science while expanding the roles taken by health economists.