“…Numerous studies, including six RCTs [4,7,38,51,63,71], failed to show any positive effects on quality associated with practice guidelines [5,10,20,25,26,36]. Results were mixed in 12 studies, in which practice guidelines improved quality for certain outcomes or patient subgroups but not others [8,23,24,41,43,52,54,55,58,59,73,74]. Finally, three systematic reviews reported that clinical practice guidelines could improve the efficacy, efficiency, and cost-effectiveness of care; however, the size of effect was variable and generally small [6,27,47].…”