SERP Coherence

SERP Coherence measures a cluster's internal consistency by comparing SERP results of random keywords from the cluster with the canonical query. Coherence above 50% = cluster is consistent (OK). Below 30% = cluster combines different topics and should be split (SPLIT).

Between 30-50% = uncertainty zone requiring manual verification. It's used in cluster validation as a complement to SERP Overlap: Overlap checks BETWEEN clusters, Coherence checks WITHIN a cluster. For example: a cluster with keywords about 'garden pools' and 'hot tubs' may have low coherence (30%), suggesting a SPLIT into two separate clusters.

In practice, if coherence is low, check which keywords are 'pulling' the cluster in different directions—these are candidates for separation.