To ensure all areas of the Perth metropolitan area were covered, a Peel sub-region was added to the REIWA geography. This was defined using the suburbs within the Local Government Areas of Mandurah and Murray. Household income is defined using proportions of the Perth median household income. This is the standard definition used by many affordable housing providers. For the purposes of this study, a mortgage calculator has been used to estimate an affordable established dwelling and land price for the Perth metropolitan area.