Rand index

Common card · No. 461410

The Rand index or Rand measure (named after William M. Rand) in statistics, and in particular in data clustering, is a similarity measure between two clusterings. It compares all pairs of elements and counts how often the two clusterings agree: either both place a pair in the same cluster, or both place the pair in different clusters. The Rand index has a value between 0 and 1, with 0 indicating that the two data clusterings do not agree on any pair of points and 1 indicating that the data clusterings are exactly the same. The adjusted Rand index (ARI) is a version of the Rand index corrected for the similarity expected by chance. It is commonly used to compare a clustering algorithm's output with a reference clustering, such as known class labels or a ground-truth partition.

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