Dr. Conor O'Toole:

We looked at a couple of models. There are three main international models, one asks is the housing cost higher than 30% of net monthly income; the second says the person must be in the bottom 40% of the income distribution as well as having a high housing cost; and the third proposes taking one of the first two models and seeing how much people have left after they have paid for their housing. The conclusion we have drawn in our paper is that we want to get somewhere between the 30% and 40% models, for the low income households to pay a maximum of 30% of their income and allow that stagger up a bit because there are higher and middle income households which do not have sufficient resources available after paying for their housing. In general our definition is approximately a maximum of 30% of income for the bottom 40% of the income distribution. Maybe it should be lower as other commentators have said for very low income households but then come up to middle income earners to take their housing costs into account.