Cohen's Kappa Calculator
Calculate unweighted Cohen kappa from a square two-rater agreement table.
At a glance
- Computes
- Unweighted Cohen's kappa, observed and chance agreement, and the agreement table.
- You supply
- A square table of counts where two raters used the same categories.
- Use when
- Two raters, one set of nominal categories, and you need agreement corrected for chance.
- Not for
- Ordered categories where a near miss should count, or more than two raters.
Cohen's kappa
Enter a table
Rows are rater 1, columns are rater 2.
| Metric | Value |
|---|
| Category | Rater 1 | Rater 2 |
|---|
Treat interpretation bands as context-specific. Kappa measures agreement beyond chance, not correctness.
kappa = (observed agreement - expected agreement) / (1 - expected agreement)
How?
How this is calculated
Observed agreement is the diagonal count divided by total rated items. Expected agreement is computed from the row and column marginals. This v1 calculator reports unweighted Cohen's kappa for nominal categories.
Formula: kappa = (observed agreement - expected agreement) / (1 - expected agreement)
Sources
- Penn State STAT 509 Cohen's Kappa. Penn State. Retrieved .
- scikit-learn cohen_kappa_score. scikit-learn. Retrieved .
Method last reviewed