Mortgage affordability indicator (MAID)

Latest release
Census of Population and Housing: Census dictionary
Reference period


This variable allocates an in scope household to one of two categories:

  • mortgage repayments less than or equal to 30% of household income
  • mortgage repayments more than 30% of household income.


Occupied private dwellings owned with a mortgage or purchased under a shared equity scheme  


1Households where mortgage repayments are less than or equal to 30% of household income
2Households where mortgage repayments are more than 30% of household income
3Unable to be determined
@Not applicable

Number of categories: 4

Not applicable (@) category comprises:

  • Unoccupied private dwellings
  • Visitor only households
  • Non-private dwellings
  • Migratory, off-shore and shipping SA1s
  • Other non-classifiable dwellings
  • Tenure type (TEND) - Owned outright, Rented, Occupied rent-free, Occupied under a life tenure scheme, Other tenure type, Not stated, Not applicable

Question(s) from the Census form

What is the total of all income the person usually receives?

Is this dwelling: (please open this section to view response categories)

How much does your household pay for this dwelling?

How this variable is created

The Mortgage affordability indicator is calculated by dividing Mortgage repayments (MRED) by an imputed household income. Both variables are expressed as single dollar values. The calculation determines whether mortgage repayments are:

  • less than or equal to 30% of household income
  • more than 30% of household income

The Census collects the income of each person in the household aged 15 years or over in ranges. To sum these personal income values to calculate a household income, a specific dollar amount is allocated to each person. A median dollar value for each range, derived using data from the Survey of Income and Housing, is used for this purpose. For more information about this survey see the Survey of Income and Housing, User Guide. 

Mortgage repayments are already collected in a single dollar amount.

Mortgage affordability indicator is coded to ‘Unable to be determined’ where:

  • Mortgage (monthly) dollar value (MRED) is Not stated
  • at least one resident aged 15 and over was either not at home on Census Night or did not state their Total personal income (INCP)
  • no residents aged 15 and over who were at home on Census Night stated their Total personal income (INCP)

History and changes

This is a new variable for 2021. QuickStats will use the Mortgage affordability indicator variable, and therefore comparisons shouldn’t be made with previous Census data in QuickStats.

In previous censuses, a measure of mortgage affordability could only be obtained from QuickStats. This measure was different from MAID as it used all occupied private dwellings whether owned outright, owned with a mortgage or rented, as the denominator population.

MAID only applies to dwellings owned with a mortgage or purchased under a shared equity scheme, which is a more accurate representation of the population to measure mortgage affordability.

Data use considerations

As housing costs are usually a major component of total living costs they are often analysed in relation to income and referred to as a housing affordability ratio. However, comparisons using these measures are subject to certain limitations.

As described above, the Census collects personal income in ranges. For this purpose, a single median value for each income range is calculated. It should also be noted that individuals may tend to understate their incomes on the Census, compared with the amounts that would be reported in surveys designed specifically to measure incomes. As a result of these limitations, the use of Census imputed incomes in the calculation of each household’s housing costs to income ratio may significantly overstate the true proportion of households with mortgage repayments greater than 30% of income.

Mortgage repayments may be greater than 30% of income for a number of reasons, and do not necessarily indicate being in financial stress.

  • Mortgage repayments normally include both an interest component and a principal or capital component. For some analyses, repayments of principal may be considered a form of saving rather than a housing cost.
  • High mortgage repayments may reflect a choice to buy a more expensive home, for example in an area that is close to their place of employment, or a preference for a relatively high standard of housing compared with other consumption possibilities.
  • Some households choose to pay more than the minimum required payment, to pay off a mortgage faster.

This variable does not have a non-response rate as it is created during Census processing by using responses from more than one question on the Census form. 

Related variables and glossary terms

  • Tenure type (TEND)
  • Total personal income (weekly) (INCP)
  • Mortgage repayment (monthly) (MRED)
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