The Role of Decision Models in Health Care Policy: A Case Study

Background. In 2009, the Centers for Medicare and Medicaid Services (CMS) underwent a National Coverage Determination on computed tomography colonography (CTC) to screen for colorectal cancer. The Cancer Intervention & Surveillance Network developed decision models to inform this decision. The purpose of our study was to investigate the role of models in this decision. Methods. We performed a descriptive case study. We conducted semistructured telephone interviews with members of the CMS coverage and analysis group (CAG) and Medicare Coverage and Analysis Advisory Committee (MEDCAC) panelists. Informed by previously published literature, we developed a coding scheme to analyze interview transcripts, MEDCAC meeting transcripts, and the final CMS decision memo. Results. Four members of the CAG and 8 MEDCAC panelists were interviewed. The total number of codes across all study documents was 772. We found evidence that decision makers believed in the adequacy of models to inform decision making. In interview transcripts, the code Models Are Adequate to Inform was more frequent than the code Models Are Inadequate to Inform (47 times v. 5). Discussion of model conceptualization dominated the MEDCAC meeting (Model Conceptualization assigned 113 times) and was frequently discussed during interviews (Model Conceptualization assigned 84 times). We also found evidence that the models helped to focus the policy discussion. Across study documents, the codes Focus on Cost, Focus on ClinicalHealth Impact, and Focus on Inadequacy of Evidence Base were assigned 99, 98, and 97 times, respectively. Conclusions. Decision makers involved in the CTC decision believed in the adequacy of models to inform coverage decisions. The model played a role in focusing the CTC coverage policy discussion.