“…Some studies reported the absolute numbers of interventions (Hilton, 1976; Knauert et al., 2019; Monsén & Edéll‐Gustafsson, 2005; Uğraş & Öztekin, 2007), but others did not (Bihari et al., 2012; Cicek et al., 2014; Freedman et al., 1999). The number of interventions was the main parameter in 10 studies (Casida et al., 2018; Gabor et al., 2003; Giusti et al., 2016; Hacker et al., 2013; Hamze et al., 2015; Le et al., 2012; Ritmala‐Castren et al., 2015; Tamburri et al., 2004; Uğraş & Öztekin, 2007; Ҫelik et al., 2005). In nine studies (Bihari et al., 2012; Cicek et al., 2014; Elliott et al., 2013; Freedman et al., 1999; Hilton, 1976; Knauert et al., 2019; Li et al., 2011; Monsén & Edéll‐Gustafsson, 2005; Patel et al., 2014), the number of interventions was one of the parameters (alongside environmental factors, sleep quality, etc.)…”