Case: Reconciling submitted vs indexed found 14% gap

Case: Reconciling submitted vs indexed found 14% gap
GSC showed 320,000 submitted but only 275,000 indexed. The team had no view into which URLs were missing.
What we did:
— Exported the indexed set and diffed against sitemap URLs
— Bucketed the 45,000 gap by reason: thin content, soft-404, slow pages
— Fixed the largest bucket (thin content, 19,000 URLs) first
Measured outcome over 8 weeks:
— Indexed: 275,000 → 309,000
— Submitted-vs-indexed gap: 14% → 3%
Checklist:
✅ Export indexed URLs monthly
✅ Diff against current sitemap
✅ Bucket the gap by GSC reason, fix largest first
Definition of done: submitted-vs-indexed gap tracked monthly and held under 5%.