“…For an assessment in terms of the conceptual use of GR, we looked for conclusive definitions of GR in the studies and tracked quotations and references that might expose a theoretical discussion of GR. While we only found 21 studies offering a conclusive definition of GR (Burgess and d' Agincourt-Canning, 2001;d' Agincourt-Canning, 2001Downing, 2005;Hallowell et al, 2006;Arribas-Ayllon et al, 2008a,b, 2011Bickerstaff et al, 2008;Etchegary and Fowler, 2008;Etchegary et al, 2009Etchegary et al, , 2015Raz and Schicktanz, 2009;Dancyger et al, 2010;Hines et al, 2010;Clarke et al, 2011;Weiner, 2011;Donnelly et al, 2013;Boardman, 2014b;D' Audiffret Van Haecke and de Montgolfier, 2015;Ross, 2015), all but 17 of the included studies made reference to non-empirical literature, such as philosophical or bioethical papers referring to or using GR (cf. Data Sheet 1).…”