Comparison study of specificity and sensitivity in three search tools for qualitative systematic reviews

For those of you interested in systematic review: a recent article:
Methley, A. et al. (2014) PICO, PICOS and SPIDER: a comparison study of specificity and sensitivity in three search tools for qualitative systematic reviews. BMC Health Services Research, 14:579. doi:10.1186/s12913-014-0579-0 There's an open access version at http://www.biomedcentral.com/1472-6963/14/579/abstract
Photo by Sheila Webber: baby carrots, Blackheath market, January 2015