Determining the scope of the review and the questions it will address

Systematic reviews can address any question that can be answered by a primary research study. Developing the questions is a critical part of the research process. Cochrane Reviews can focus on broad questions, or be more narrowly defined. There are advantages and disadvantages of each. Since systematic reviews are intended for use in healthcare decision making, review teams should ensure not only the application of robust methodology, but also that the review question is meaningful for healthcare decision making. The chapter discusses two approaches: using results from existing research priority-setting exercises to define the review question; and in the absence of, or in addition to, existing research priority-setting exercises, engaging with stakeholders to define review questions and establish their relevance to policy and practice. Logic models can be useful in systematic reviews when considering whether failure to find a beneficial effect of an intervention is due to a theory failure, an implementation failure, or both.