Planning Policy Statement 3, published in November 2006, says that local development documents and regional spatial strategies should be informed by a robust, shared evidence base, in particular, of housing need and demand, and that this evidence should be used to set an overall target for the amount of affordable housing to be provided.
In August 2007, the Government published guidance on completing a strategic housing market assessment. The guidance sets out a framework that local authorities and regional bodies can follow to develop a good understanding of how housing markets operate. It promotes an approach to assessing housing need and demand which can inform the development of local development documents and regional spatial strategy planning for housing policies.