The past 30 years have seen significant changes in the ways children are conceptualised within research, policy and practice. The UN Convention on the Rights of the Child (CRC) (UNICEF 1989) established children as individual holders of rights to survival and development, protection and participation. Particularly, participation rights have become associated with children's rights to have a voice and power over decisions of relevance to them (Montgomery, 2010). An increasing number of countries have incorporated children's rights into policies and practice, some by integrating children's participation rights into national constitutions, others by building them into child-specific legislations (European Commission, 2015), for example, education or welfare services (Heimer et al., 2018; Križ and Skivenes, 2017). Schools and other childhood settings and organisations often make reference to the rights of children to have a say over matters of importance to them, although this is interpreted across countries in significantly different ways. Within research, it is also generally acknowledged that children's experiences need to be included and studied in their own right (Christensen and James, 2008a; Kellett et al., 2004; O’Kane, 2008; Prout, 2005; Wyness, 2015) and that children must be considered as research subjects rather than as objects of research (Horgan, 2017; Kellett, 2005).

There is now a well-established body of literature on children's rights and agency (James, 2011; Oswell, 2013; Smith, 2007) which incorporates the idea that children have global entitlements and makes research-based assumptions about children's capacities and contributions. Within this literature, the rights of children to have a voice, exercise agency and participate in matters of importance to them is often associated, and at times conflated, with the idea that children have more power. Common sense and public commentary on childhood also tends to assume that children's power derives from the increase in legal and political arrangements that give children an opportunity to make a difference in their own lives and in the lives of those around them. This linkage between rights, agency, participation and power presents the basis for one model of what we in this book refer to as kid power.