The first is our greater appreciation of the importance of how schools relate to their communities, contexts, and other social services, such as those that exist in extended or full-service schools (Cummings et al., The second is the need for schools to be interconnected and to collaborate in order to maximise positive outcomes across communities and enhance social justice (Hadfield and Chapman, 2009(63]). There is, how'ever, growing - though contested - evidence of the relationship between collaboration and school improvement (Chapman and Muijs, 2014|64]; Croft, 2015(65]), and of the challenges collaboration poses for school leaders, not least in moving from hierarchical to equal peer leadership relationships (Muijs, West and Ainscow, 2010(49]). The increasing call for leadership across systems and networks of schools provides impetus to include items on this new topic in TALIS 2018.