A primary factor in housing affordability is household income. The most common approach is to consider the percentage of income that a household is spending on housing costs.
Another method of studying affordability looks at the regular hourly wage of full-time workers who are paid only the minimum wage (as set by their local, regional, or national government). The hope is that a full-time worker will be able to afford at least a small apartment in the area that he or she works in.
Other countries look at those living in relative poverty, which is usually defined as making less than 60% of the median household income. In their policy reports, they consider the presence or absence of housing for people making 60% of the median income.