Exact McNemar Explorer
Test symmetry of discordant classifications in a paired binary table.
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Test symmetry of discordant classifications in a paired binary table. All default values are fictional.
Calculation results
Complete pairs: 100; discordant pairs: 10
Exact two-sided p: 0.109375
Assumptions and limits
Conditional exact two-sided McNemar p = min(1, 2 × Pr[Binomial(b+c, 0.5) ≤ min(b,c)]). The null concerns equal probabilities of the two discordant directions, not independence of the two measurements. Independent pairs, exactly two occasions/conditions, and binary classifications are required. At most 1,000 discordant pairs are accepted for this implementation. This is not the mid-p or chi-square approximation. With no discordance the conventional p is 1, but there is no discordant information. A p-value does not quantify effect size, equivalence or clinical importance; report the full table and paired effect with an appropriate interval separately.
statsmodels: exact McNemar test · Read the practical guide · Download blank worksheet (TXT)