In both censuses, the "spouse" and "unmarried partner" response categories were defined and asked the same way. However, there were important differences in data processing that mean that some of the data are not comparable, limiting the usefulness of comparisons of the number of same-sex unmarried partners between these two censuses.

In both censuses, if a person was identified as the "spouse" of the householder and was the same sex as the householder, the "spouse" response was flagged for further review and allocation, that is, assignment of a value other than that originally reported, based on other data on the form. In 1990, the edit and allocation procedures did not allow same-sex "spouse" combinations to occur, thus resulting in the allocation of one of these two items in order to achieve editing consistency among the responses.