Schema Coverage refers to the breadth and quality of JSON-LD structured data on your pages. It tells AI systems what your page is about in machine-readable terms — your organization, products, FAQs, articles, and relationships between entities.
SEODiff looks for 10 Schema.org types and scores based on presence and diversity:
The Schema Score formula: Organization types give +40, Product/Service types give +40, and additional schema blocks give bonus points (up to +20 for 10+ blocks). The SchemaCoverage() function also counts coverage across 7 distinct schema categories.
Without structured data, AI systems must infer what your page is about from unstructured text. This leads to misidentification, hallucination, and missed citations. Schema acts as a "cheat sheet" that tells AI crawlers exactly who you are, what you offer, and how your content is organized.