“…Empirical findings from the Netherlands (e.g., Honingh and Hooge, 2014), the USA (Goddard et al, 2015; Supovitz et al, 2010), and Germany (e.g., Pietsch et al, 2016; Pietsch and Tulowitzki, 2017) indicate a relationship between principal leadership and teacher collaboration. In particular, studies from Germany found a relationship between teacher collaboration and principal leadership in cases where principals provided structures required for teacher collaboration, for instance, by allocating time slots for collaboration (Harazd and Drossel, 2011; Richter and Pant, 2016; Warwas et al, 2019) or promoting teacher interaction (e.g., by appreciating teachers who work together; Harazd and Drossel, 2011). Findings from a longitudinal qualitative study on nine teachers in the United States suggest it is not sufficient for principals to merely provide structures for teacher collaboration (Szczesiul and Huizenga, 2014), but that principals should “create a culture of shared vision, purpose, and goals, in order to create interdependence and collective responsibility within teams” (Szczesiul and Huizenga, 2014, p. 187).…”