“…These findings are consistent with those of previous studies reporting that children who participated in whole-school programmes, such as eco-schools or schools that promote a healthy lifestyle, had a deeper understanding of these issues; furthermore, they learned about various global and local issues related to sustainability with support of their teachers (Davis, 2005;Davison, Davison, Reed, Halden, & Dillon, 2003;Lewis, Mansfield, & Baudains, 2010;Mackey, 2012). Nevertheless, two previous studies that compared eco-certified and non-eco-certified preschools in terms of children's knowledge and practices of environmental and sustainability issues using statistical analysis did not find any statistically significant differences (Borg, et al, 2017a(Borg, et al, , 2017b. Therefore, it is important to conduct a large-scale study of sufficient statistical power to investigate whether eco-certification plays any role in developing children's knowledge, attitudes and behaviours of particular relevance to a sustainable society.…”