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McNemar Test Explorer

Matched test

Investigate matched, binary outcomes with contingency visuals, effect-size diagnostics, and ready-to-share reporting.

TEST OVERVIEW & EQUATIONS

McNemars test spotlights the switcherspairs where the two conditions disagree. Only those one-sided wins inform the hypothesis test.

\[ \begin{aligned} \chi^2_{\text{McNemar}} &= \frac{(b - c)^2}{b + c} \\ \chi^2_{\text{Corrected}} &= \frac{(|b - c| - 1)^2}{b + c} \\ p_{\text{exact}} &= 2 \times \min \Bigg( \sum_{i=0}^{b} \binom{b + c}{i} 0.5^{b + c},\; \sum_{i=0}^{c} \binom{b + c}{i} 0.5^{b + c} \Bigg) \end{aligned} \]

Where:

  • \(b\) counts people who only converted under Condition A, \(c\) only under Condition B.
  • Continuity-corrected \(\chi^2\) keeps Type I error in check when switchers are scarce; the exact approach doubles the smaller binomial tail.
  • If one-sided wins favor a condition more than chance allows, we reject equal success probabilities.
Additional Notes

See the McNemar test article for deeper derivations and extensions (matched pairs of nominal data).

MARKETING SCENARIOS

Select a preset to auto-fill matched outcomes for common diagnostics (e.g., creative tests with before/after responses). Drop additional .txt files in the scenarios folder and index them to extend the menu.

INPUTS & SETTINGS

Select Data Entry / Upload Mode

Matched Outcome Table

Enter how many people fall into each combination of outcome and condition. Click the labels directly in the table to customize them.

Condition B
Positive
Negative
Condition A
 Positive
Negative
Total condition A positive: 0
Total condition A negative: 0
Total pairs: 0

Upload a single-row CSV/TSV that includes matched counts, labels, α, and method preference.

Drag & Drop raw data file (.csv, .tsv, .txt)

Single-row summary for 2x2 table: include labels, cell counts, and optional alpha/method fields.

No summary file uploaded.

Upload row-level matched outcomes. Each row should contain Condition A and Condition B outcomes.

Drag & Drop raw data file (.csv, .tsv, .txt)

Two columns with headers (Condition A, Condition B); entries can be text labels or 0/1 outcomes.

No raw file uploaded.

Confidence Level & Reporting

Set the significance level for all McNemar reporting.

Analysis Settings

Stay with the default unless your testing doc specifies otherwise.

Statistic guidance

  • Chi-square (corrected): default, controls false positives when switchers are scarce.
  • Chi-square (no correction): use when you have 25+ switchers and want slightly more power.
  • Exact binomial: safest when you have only a handful of switchers.
Advanced: Override the statistic

VISUAL OUTPUT

Contingency Heatmap

TEST RESULTS

Method: –
Test statistic: –
Degrees of freedom: 1
p-value: –
Odds ratio (CI): –
Decision (α): –
Interpretation: –

APA-Style Statistical Reporting

Managerial Interpretation

Switcher Narrative

McNemar Test Output

Enter paired counts to run the test.

Summary Table

Cell Count Share of total Notes
Enter counts to see the full table.

DIAGNOSTICS & ASSUMPTIONS

Diagnostics & Assumption Tests

Run an analysis to populate diagnostics on switcher counts, balance, and assumption risk.