PICO, PICOS and SPIDER: a comparison study of specificity and sensitivity in three search tools for qualitative systematic reviews. Methley AM, Campbell S, Chew-Graham C, McNally R, Cheraghi-Sohi S BMC Health Serv Res. 2014 Nov 21; 14(1):579. Epub 2014 Nov 21. PMID: 25413154. Abstract CommentRecommendBookmarkWatch