Kappa Agreement Analysis: Attribute Judgment Consistency Online
What is Kappa?
The Kappa coefficient measures how much two or more raters agree on classifying the same samples beyond what would happen by chance: Îș = (Po â Pe)/(1 â Pe), where Po is the observed agreement rate and Pe the expected agreement rate. It applies to go/no-go judgments, defect grading and sensory classification, and is the core metric for attribute measurement system analysis and rater capability. A low Kappa means human factors dominate the verdicts and training or standardization is needed.
When to Use It
Use it for attribute MSA, qualifying inspectors, checking consistency of sensory panels, and verifying that different evaluators apply the same judgment standard. With two raters use Cohen Kappa; with three or more use Fleiss Kappa. The tool also outputs per-category agreement and a pairwise Kappa matrix to locate the categories and rater pairs with the largest disagreement.
How to Use It (Step by Step)
Select samples that cover the acceptance boundary, including borderline units, number them, and have each rater judge independently. For within-rater consistency, run two rounds separated by enough time that raters cannot remember the order. Enter the judgment matrix and the tool outputs Kappa values and agreement percentages, plus agreement of each rater against a reference standard to expose systematic bias.
Key Formulas / Example
Kappa is Îș = (Po â Pe)/(1 â Pe). The Landis & Koch scale interprets values: below 0 poor, 0-0.20 slight, 0.21-0.40 fair, 0.41-0.60 moderate, 0.61-0.80 substantial, and 0.81-1.00 almost perfect. Attribute measurement systems are generally required to reach Kappa â„ 0.75, and critical accept/reject judgments often require 0.8 or higher.