“…They are noteworthy because they appeared to be founded on a set of items that have been the focus of some validation efforts, but in each case, adaptations were made without clear justification. All six of these studies (Peter & Valkenburg, 2009, 2011bVandenbosch & van Oosten, 2017;van Oosten, 2016;Vogels, 2018;Vogels & O'Sullivan, 2019), for example, used only four of the original five items proposed by Peter and Valkenburg (2006), with no mention of why the fifth item (i.e., the use of "erotic contact sites", p. 186), with which the scale validity was originally supported, was excluded. Further, the original scale asked about pornography use over the past six months, but three of these studies used either a two month or a four month assessment window.…”