Evidence maps: a tool to guide research agenda setting.

A surprisingly huge proportion of medical research still shows poor quality in design, conduct and analysis, leading to far from optimal robustness of findings and validity of conclusions. Research waste remains a problem caused by a number of reasons. Asking the wrong research questions and ignoring the existing evidence are possible preventable ones. Evidence maps are tools that may aid in guiding clinical investigators and help in agenda setting of future research. In this article, we explain how they serve such a goal and outline the steps required to build effective evidence maps.