Which design for which question? An exploration toward a translation table for comparative effectiveness research

In this paper, we explore the relative value that different methods offer in answering some stereotypical comparative effectiveness research questions with the goal of informing development of a 'translation table'--a selection tool for choosing appropriate methods for specific comparative effectiveness research questions. This paper was written as a parallel effort to Greenfield and Kaplan (also in this volume) to support the endeavor described in the manuscript by Tunis et al. (also in this volume). Originally based on four cases, the current article has been shortened to two cases for the current discussion. These cases represent research priorities proposed to orient the work of the Patient-Centered Outcomes Research Institute, comparative clinical effectiveness and comparative health services.