Index Coverage
Index coverage refers to which of a site's URLs a search engine has crawled and included in its index, and the reasons others are excluded. Google Search Console's Page Indexing report groups URLs by status such as indexed, crawled but not indexed, and excluded.
Why It Matters
A page cannot rank if it is not indexed. Monitoring coverage reveals when valuable pages are silently excluded or when low-value pages bloat the index, so you can fix the causes before they cost traffic.
Common Mistake
Treating high indexed counts as success. Thin, duplicate, or auto-generated pages padding the index can dilute site quality; the goal is having the right pages indexed, not the most pages indexed.