What is Passage-Level Indexing?
Passage ranking is Google's ability to identify that an individual section of a page is relevant to a query. Google clarified that it still indexes the page as a whole; “passage indexing” was an early name, not a separate paragraph index.
Other retrieval systems can also select excerpts, but their private selection systems should not be described as equivalent to Google's passage-ranking system without primary evidence.
Clear headings, direct answers, accurate claims, and self-contained context can make a section easier for people and machines to understand. CiteFuel's passage score is an internal writing heuristic: there is no universal 40–150-word requirement and no paragraph format guarantees ranking or citation.