Recall for a quantitative response, when responses are recorded as matched pairs, the question of interest is not usually whether there's a relationship or correlation between the two responses but rather whether the means of the responses are equal. Likewise, when categorical responses are paired, such as when subjects respond to the same question at two different time points, we could carry out the usual test of independence for categorical variables, but more specifically, we may be more interested in whether proportions are equal or in the extent that the subjects' opinions agree over the two-time points.