The data synthesized within a systematic review are the results extracted from individual research studies relevant to the review question. As much as meta-analysis is preferred, it is not always possible in a systematic review if the included studies vary greatly from each other, either in terms of how they are conducted (different interventions), who they are performed on (different populations) or in their final result. When meta-analysis isn’t possible, common alternatives for the synthesis of quantitative data in a systematic review include narrative summary of results, vote counting, and presenting data via tables. Before discussing meta-analysis, alternative methods to synthesis are discussed.