“…Three gray literature studies relied on informal methods involving parent recollection to examine adherence (Blechschmidt, 2016;Nowinski, 2009;Shephard et al, 2019). Given methodological concerns related to the parent recollection method, we focus on the more rigorous, published studies in our description of results (Cheung et al, 2014;Elias et al, 2020;Pritchard et al, 2014;Quillen et al, 2011;Waber et al, 2017). More information, including the majority of findings from gray literature studies, is available in Table S5.…”