Specialty › Power (hypothesis tests)

McNemar paired proportions

Power analysis for McNemar's paired-proportion test uses the Connor (1987) approximation.

What is McNemar paired proportions?

For McNemar's test, what matters is the *discordant-pair* count, not the total n. The Connor approximation parameterises power by p_disc (overall discordance rate) and the signed p_diff = p_{01} − p_{10}.

When should I use McNemar paired proportions?

  • Powering paired-binary studies (before/after, two raters on same items).

What data does it need?

Discordance rate p_disc + signed difference p_diff + α + n or power.

What does it report?

Pairs n or achieved power.

How do I interpret the result?

When the discordance rate is low (most pairs agree), required n inflates fast — McNemar power is set by discordant pairs, not total pairs.

See also

References

  • Connor (1987). Sample-size selection in matched pair studies. Biometrics 43(1).