The Median multiple or Median house price to income ratio is a housing indicator used to indicate the affordability of housing in any given community. The Median house price to income ratio WAS the primary indicator H1 of the 1991 World Bank/UNCHS Housing Indicator system. It was subsequently used as a measure of affordability by the UN Commission for Sustainable Development, the National Association of Realtors, State of the Environment 2003 Tasmania; and the Mortgage Guide UK along with many other organisations.