Statistical tests for proportions in matched groups
(This is a sub-page of the Medical statistics page.)
Used for proportions in matched groups.
Situation in which McNemar test can be used
Two individually matched groups, each of size N (N pairs of observations); qualitative binary variable with unknown population proportions π1 and π2 in one category of the variable. This category is denoted by a + sign below. Often the groups are cases and controls in a pair-matched case-control study, and the binary variable is exposure/non-exposure to a risk factor.
Assumptions/requirements for McNemar test:
Null hypothesis for McNemar test:
That the proportions π1 and π2 are equal.
Method for McNemar test:
Lay out the data in a two-by-two table as
where the classification is based on N pairs of observations, and the + and - signs refer to the categories of binary variable.