Passage Indexing

Definition

Passage indexing (Google calls it "passage ranking") is a technique Google launched in 2021 where it identifies and independently evaluates individual passages within a page, rather than just assessing the page as a whole. This means a long, comprehensive page can rank for a specific query answered in just one section — even if that section is buried and the overall page topic is broader. Google uses language models to identify self-contained, well-structured passages and assess their relevance to specific queries. Passage indexing is distinct from featured snippets: featured snippets are shown in a special SERP box, while passage ranking affects regular SERP positions.

Why it matters for SEO

Passage indexing rewards well-structured, comprehensive long-form content. If your page has a clearly delineated section (H2/H3 heading, a few paragraphs, a specific answer) that directly addresses a specific query, it can rank for that query even if the page as a whole targets a different primary topic. This is why content chunkability — writing in discrete, self-contained sections with descriptive headings — matters not just for human readers but for passage ranking. It also directly parallels how AI citation works: large language models retrieve passages, not pages, when generating answers.

How DeepSEOAnalysis checks this

The audit evaluates content chunkability as part of the AI visibility score: average word count per section (between headings), heading density, and whether sections read as self-contained (topic sentence → body → conclusion). Pages with very long walls of text (no H2/H3 breaks for 600+ words) are flagged as poor for both passage ranking and AI citation. The question-heading ratio check also surfaces opportunities to structure sections as explicit question-and-answer passages.

Useful tools and resources

• AI visibility audit
• AI visibility research report