This chapter aims to address an important aspect of the hypothesis, namely to examine the structure of systems of housing supply. Chapter 4 provides an important link between Chapter 3, which examined the systems of supply in the three countries from a ‘state-market’ perspective, and Chapter 5 which looks at housing production outcomes. This chapter aims to provide a discussion on the different ways in which the three housing systems can be conceptualised, paying specific attention in the conclusion to similarities and differences arising from each perspective. Conclusions from this and the previous chapter will be compared and contrasted in the light of the investigations of the following chapter.