What it is, and what it is not
It is a working idea SEOs use, not a score Google publishes, and no tool can read it off your site. What you can see are its effects: pages on a subject you cover well rank sooner, and rank for longer and more specific searches you never targeted.
How sites build it
Depth on one subject beats a page on every subject:
- Cover the subtopics and follow-up questions of one subject before moving to the next.
- Link each page to its hub page and to the pages beside it.
- Give each search one page, so your pages add up instead of competing.
- Keep the pages current; a subject you covered in 2022 and left alone looks abandoned.
How to tell it is working
In Search Console, watch the number of queries each page on the subject gets impressions for. When new pages on the subject start ranking within weeks rather than months, the coverage is paying off.