This paper aims to make transparent one economist’s views on density. I start by clarifying different definitions and their relationship to one another – which helps to explain why people have such very different ways of thinking about density. 

I then look at the economic principles which lie behind land use planning (rather than the physical, design and social reasons where my only competence is to raise these issues within the economic framework of efficiency and equity). I juxtapose these principles with the arguments for market allocation, concentrating particularly on what people aspire to and are able to demand – and therefore how actual densities are likely to evolve.