“…We systematically searched six different databases following PRISMA guidelines. The development of the PEH √ list is based on our (Pescatello et al, 1991(Pescatello et al, , 2004(Pescatello et al, , 2007(Pescatello et al, , 2016Keese et al, 2011;Ash et al, 2013;Headley et al, 2017;Cordeiro et al, 2018;Cilhoroz et al, 2019;Zaleski et al, 2019;Babcock et al, 2020;Farinatti et al, 2021) and others (Hacke et al, 2018;de Brito et al, 2019) long history of performing well-controlled PEH studies (Guadagnoli and Velicer, 1988;Pescatello et al, 1991Pescatello et al, , 2003Pescatello et al, , 2004Pescatello et al, , 2015aPescatello et al, , 2017Pescatello et al, , 2019Thomas et al, 2006;Moher et al, 2009;Casonatto et al, 2011;Johnson et al, 2014;Matzer et al, 2017) as well as the methodological study quality standards of the Cochrane risk of bias tool (Higgins et al, 2011) and Downs and Black checklist for methodological quality (Downs and Black, 1998). The PEH √ list is comprehensive addressing essential study design considerations.…”