“…Some studies are national case studies (Bryna Sanger, 2001;Van Berkel and Van der Aa, 2005); some adopt a comparative approach, comparing, among others, the ways in which markets were introduced, developments in the regulation of markets by the state, the nature of contracts between service purchasers and service providers, and the impact of markets on services (Considine, 2001;Bredgaard and Larsen, 2005;Struyven and Steurs, 2005;Sol and Westerveld, 2005). Most studies focus on a limited number of countries only, as these are considered to be at the vanguard of introducing quasi-markets to activation services: Australia, the UK, the US and the Netherlands.…”