A test for dependent categorical data, such as yes/no data before & after a treatment. The McNemar-Bowker test generalizes McNemar's test for $k>2$ categories. The tests assess whether the population proportions in each pair of corresponding symmetric cells are equal.
McNemar's test is a test for dependent categorical data. Given two variables with $2$ categories (McNemar's test) or $k$ categories (McNemar-Bowker test) that form a square contingency table, the tests assess whether the population proportions in every off-diagonal cell is equal to that in the corresponding symmetric cell.
