The Housing Affordability Index, calculated by the Runstad Center for Real Estate Studies, measures the ability of a middle-income family to carry the mortgage payments on a median-price home. When the index is 100 there is a balance
between the family’s ability to pay and the cost. Higher indexes indicate housing is more affordable.

For example, an index of 126 means that a median-income family has 26 percent more income than the bare minimum required to qualify for a mortgage on a median-price home. An index of 80 means that a median-income family has less income than the minimum required.

This dataset provides a quarterly count of affordable housing units by housing project type.