NavBoost
NavBoost is a Google ranking system described in the U.S. government's antitrust case against Google. The court's 2024 opinion says it remembers which results people clicked after a search, and that Google has used 13 months of user data for it since 2017. Google's public guide to its ranking systems doesn't list it.
Source: U.S. District Court for the District of Columbia, United States v. Google LLC, Memorandum Opinion (Judge Amit P. Mehta, August 5, 2024), findings of fact 96 and 102, checked October 29, 2026
What NavBoost means for your business
What's known for sure comes from sworn testimony and the judge's findings. Eric Lehman, a former Google engineer, told the court in 2023 that NavBoost isn't a machine learning system and called it "just a big table" of how many clicks each page got for each search. The opinion says Google used 18 months of data before 2017, and quotes an internal Google document that called NavBoost one of its most powerful ranking parts over the years.
The name also appears as field and module names in the Google documents leaked in 2024, which our glossary covers under the Google API leak.
We don't know how much NavBoost weighs today, how it treats any one site, or whether it has anything to do with AI Overviews. What the record does show is that Google keeps track of what searchers choose. We'd read that as one more reason for a title that matches the page and a page that answers the search, so the people who click find what they came for.
If you'd rather judge search work by numbers you can check than by guesses about Google's inner workings, the numbers we report each quarter are all listed, along with their limits.
Source: U.S. Department of Justice, Trial exhibit PXRD016, testimony of Eric Lehman (September 20, 2023), checked October 29, 2026
Last reviewed October 29, 2026. All terms
How AI answers it today
On October 29, 2026, Google's AI Overview cited SEO blogs, LinkedIn, Reddit and YouTube, no court record, and listed kinds of clicks and ranking effects the court's opinion doesn't describe. ChatGPT cited the opinion and Search Engine Land, then offered tips for optimizing for NavBoost.
Our run through ChatGPT and Google's AI Overview, October 29, 2026. A sample, not what every buyer sees.
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