Rand Index#

The Adjusted Rand Index is a measure of similarity between a clustering and some ground-truth that is adjusted for chance. It considers all pairs of samples that are assigned in the same or different clusters in the predicted and empirical clusterings.

Estimator Compatibility: Regressor

Output Range: -1 to 1


This metric does not have any parameters.


use Rubix\ML\CrossValidation\Metrics\RandIndex;

$metric = new RandIndex();


  • W. M. Rand. (1971). Objective Criteria for the Evaluation of Clustering Methods.