Equivalised income
This adjustment is made on the basis of equivalence factors. The equivalence factor reflects the economies of scale resulting from having a shared household. Using the equivalence factors, all incomes are converted to the income of a single-person household. This allows for a comparison of the level of prosperity across different households. The equivalised income is a measure for the prosperity of (the members of) a household.
For this study, five equal groups were formed based on the equivalised income of the household of which the person is a member.