NavBoost & Click-Signal Glossary: Key Terms Explained

About This Glossary

The vocabulary surrounding Google's click-based ranking systems became substantially more precise after two events. The first was the 2023 U.S. Department of Justice antitrust trial, during which Pandu Nayak, Google's Vice President of Search, testified under oath about NavBoost and described it as one of the "most important" ranking signals. The second was the May 2024 leak of internal Google API documentation, comprising roughly 2,596 modules and more than 14,000 attributes, which exposed the specific field names and mechanisms Google uses to process click data.

Before those disclosures, much of the terminology in this field was speculative or borrowed from third-party SEO commentary. After them, terms such as goodClicks, squashedClicks, and lastLongestClicks can be cited as the literal field names that appeared in Google's own documentation. This glossary distinguishes between terms that are directly confirmed by the leak or sworn testimony and terms that remain interpretive. For a foundational overview before reading definitions, see What is NavBoost?

Entries are arranged alphabetically. Field names from the API leak are shown in monospace where applicable. Each definition links to the most relevant analysis elsewhere on this site for readers who want the full treatment of a given concept.

How To Read These Entries

Definitions describe what the leak and testimony establish, and they hedge where the evidence is interpretive rather than confirmed. Where a term is widely used in SEO commentary but not literally present in Google's documentation, the entry notes that distinction. For a complete bibliography of primary sources, see NavBoost Research Sources.

Terms: A–C

AI Mode

Google's conversational search interface, launched in March 2025, which replaces the traditional results page with a generated answer assembled from across the web. Industry measurements reported that a large majority of AI Mode sessions end without a click to any external site, intensifying the broader zero-click trend. AI Mode reshapes the click data that systems like NavBoost depend on. See Google AI Mode and the Future of Clicks.

AI Overviews

The generative answer summaries Google places above traditional organic results for many queries. Ahrefs measured roughly a 58% reduction in clicks to the top organic result when an AI Overview is present, and SISTRIX data places position-1 CTR with an AI Overview present in the 11–15% range. See How AI Overviews Changed CTR.

badClicks

A click type confirmed in the 2024 API leak. A badClick occurs when a user clicks a result and quickly returns to the search results page, a behavior known as pogo-sticking that signals dissatisfaction. badClicks act as a negative ranking signal. See NavBoost Click Types and Pogo-Sticking.

Branded Search

Searches that include a brand or domain name, such as querying a company by name rather than by a generic topic. Branded queries are often navigational and produce strong, repeatable click patterns that NavBoost can read as a vote of confidence in a specific result. See Branded Search as a Ranking Signal.

chromeInTotal

A site-level field surfaced in the API leak that appears to count views of a site recorded through Chrome. Its presence in the documentation is part of the evidence that Google collects browser-derived behavioral data at the site level, contradicting earlier public denials that Chrome data informs ranking. See How Google Uses Chrome Data in Rankings.

Click-Through Rate (CTR)

The proportion of users who click a result after seeing it in the SERP, expressed as clicks divided by impressions. CTR is an input to NavBoost rather than a standalone ranking factor, and its value varies widely by position and SERP layout: SISTRIX places pure-organic position-1 CTR near 34.2%, while seoClarity's 750-billion-impression study reports desktop position-1 CTR near 8.17% across all SERP types. See Does CTR Affect SEO Rankings? and CTR by Search Position.

CTR Curve

The characteristic decline in click-through rate from higher to lower search positions, used to model expected clicks per rank. The curve has steepened over time: GrowthSRC's 2025 study of 200,000 keywords found position-1 CTR fell from 28% to 19% year over year, a 32% decline, as SERP features and AI Overviews absorbed clicks. See The CTR Curve.

Terms: D–G

Dwell Time

The length of time a user spends on a clicked result before returning to the SERP. Dwell time is the behavioral basis for distinguishing goodClicks from badClicks and underpins the lastLongestClick designation. There is no publicly confirmed threshold, so any specific cutoff is interpretive. See Dwell Time and SEO.

E-E-A-T

Experience, Expertise, Authoritativeness, and Trustworthiness, a framework from Google's Search Quality Rater Guidelines used to evaluate content quality. E-E-A-T is a conceptual standard applied by human raters and quality systems, not a single algorithmic score, and it operates alongside, not within, NavBoost's click-based re-ranking.

Expected CTR

The click-through rate a result is predicted to receive at a given position for a given query type, used as a baseline against which actual performance is compared. Outperforming the expected rate for a position can indicate a more compelling title or snippet, while underperforming may indicate the opposite. See The CTR Curve.

Featured Snippet

A SERP feature that displays an extracted answer above the organic results. SISTRIX data shows the snippet itself captures roughly 42.9% of clicks, while the position-1 organic listing below it sees CTR fall to about 23.3%. See Featured Snippets and CTR and How SERP Features Change CTR.

Generative Engine Optimization (GEO)

The practice of optimizing content to be cited and surfaced within AI-generated answers, including AI Overviews and AI Mode, as opposed to ranking in traditional results. GEO is a response to the growth of zero-click and generative search. See Generative Engine Optimization.

Glue

The companion system to NavBoost that applies click and interaction signals to the non-organic elements of the SERP, including knowledge panels, image packs, video carousels, and People Also Ask boxes. Where NavBoost re-ranks the ten blue links, Glue extends the same logic to universal search features. Both were described in antitrust testimony as operating since at least 2005. See Glue: Ranking Universal Search Results with Click Signals.

goodClicks

A click type confirmed in the 2024 API leak. A goodClick is a click where the user stays on the destination result for a meaningful period rather than returning to the SERP, signaling satisfaction. goodClicks act as a positive ranking signal. See NavBoost Click Types.

Terms: K–Q

Knowledge Panel

A SERP feature that presents structured information about an entity, typically in a box on the right side of desktop results. When a knowledge panel is present, SISTRIX places position-1 organic CTR near 16.7%, well below the pure-organic rate. Interactions with knowledge panels are read by Glue rather than NavBoost. See How SERP Features Change CTR.

lastLongestClicks

A click type confirmed in the 2024 API leak and widely regarded as the strongest positive signal in NavBoost. The lastLongestClick is the final and longest-dwell click in a search session, marking the result that most plausibly satisfied the user's intent after they evaluated several options. See NavBoost Click Types.

NavBoost

Google's click-based re-ranking system, operational since at least 2005, which adjusts initial rankings using historical user click behavior. Pandu Nayak described it under oath as one of the "most important" ranking signals, and a 2019 internal note attributed to a Google VP reportedly called NavBoost more powerful than the rest of ranking combined on click and precision metrics. See What is NavBoost?

Navigational Query

A search whose intent is to reach a specific known destination, such as a brand homepage or login page. Navigational queries produce highly concentrated click patterns: SISTRIX places position-1 CTR for navigational results showing sitelinks near 46.9%, the highest of any SERP layout. See Branded Search as a Ranking Signal.

Pogo-Sticking

The behavior of clicking a result, finding it unsatisfactory, and returning to the SERP to try another result. Pogo-sticking is the user action that NavBoost records as a badClick. It is distinct from bounce rate as measured in analytics tools, which Google does not use as a ranking input. See Pogo-Sticking and How to Reduce Pogo-Sticking.

Query-URL Pair

The unit on which NavBoost aggregates click data. Rather than scoring a page in isolation, NavBoost maintains a behavioral profile for each combination of a query (or query cluster) and a URL, which is why the same page can perform differently across different queries. See How NavBoost Works.

Terms: R–S

RankBrain

Google's machine-learning system, introduced in 2015, for interpreting queries, particularly novel or ambiguous ones, by mapping them into a semantic space. RankBrain handles query understanding, whereas NavBoost handles click-based re-ranking; the two operate on different parts of the pipeline. See NavBoost vs RankBrain.

Re-Ranking

The stage of Google's pipeline in which an initially scored set of results is reordered before final assembly. NavBoost operates at this stage, adjusting the order produced by content and authority signals based on accumulated click behavior. See How NavBoost Works and Twiddlers: How Google Re-Ranks Results.

Rich Results

Enhanced search listings generated from structured data, such as star ratings, FAQ accordions, or recipe details. Rich results can raise a listing's visibility and click-through rate without changing its underlying position. See Structured Data and CTR.

Search Intent

The underlying goal behind a query, commonly grouped as informational, navigational, commercial, or transactional. NavBoost is, in effect, an aggregate measure of how well a result satisfies intent, because results that match intent earn goodClicks and lastLongestClicks while mismatches earn badClicks. See Search Intent and Click Signals.

SERP Features

Non-organic elements on the results page, including ads, featured snippets, knowledge panels, shopping units, and AI Overviews. Each feature changes the click distribution: SISTRIX places position-1 CTR at 18.8% when ads are present and 13.7% when shopping units appear, versus 34.2% for pure organic. See How SERP Features Change CTR.

siteAuthority

A site-level quality field surfaced in the 2024 API leak. Its existence is significant because Google had publicly downplayed the idea of a site-wide authority metric; the field name suggests an aggregate measure of domain quality that operates alongside click signals. See The 2024 Google API Leak.

squashedClicks & unsquashedClicks

Two paired fields from the API leak. unsquashedClicks are click counts deemed genuine and reliable after filtering, while squashedClicks are the same signals after normalization that compresses extreme volumes to resist manipulation. The distinction is central to why high click volume produces diminishing returns. See NavBoost Click Types.

Squashing Function

The normalization mechanism, conceptually similar to a logarithmic or sigmoid curve, that compresses raw click signals so that extreme volumes yield diminishing returns. The squashing function is a core structural defense against click manipulation. See The NavBoost Squashing Function.

Terms: T–Z

Thirteen-Month Window

The rolling period, approximately 13 months, over which NavBoost aggregates click data for a query-URL pair. A single month contributes roughly 7.7% of the signal, which dilutes short-term manipulation, and the 13-month span captures a full seasonal cycle plus one month of overlap. See NavBoost's 13-Month Rolling Window.

Twiddler

A re-ranking function that adjusts results after the primary scoring algorithm. The 2024 leak indicated that NavBoost operates as one such layer alongside Twiddlers for freshness, quality, and result diversity, each able to boost, demote, or constrain documents before the SERP is finalized. See Twiddlers: How Google Re-Ranks Results.

Zero-Click Search

A search that ends without the user clicking any result, because the answer was satisfied on the SERP itself or by an AI response. Semrush's 2025 data places zero-click searches at 58.5% of U.S. searches, rising to roughly 83% when an AI Overview is present. Zero-click sessions reduce the volume of behavioral data feeding NavBoost. See Zero-Click Searches.

Quick Reference: Click Types at a Glance

The four click-related fields most often confused with one another are summarized below. All four are literal field names from the 2024 API leak.

Field	Meaning	Signal Direction
`goodClicks`	User clicks and stays	Positive
`badClicks`	User clicks and quickly returns (pogo-sticking)	Negative
`lastLongestClicks`	Final, longest-dwell click in a session	Strongest positive
`unsquashedClicks`	Clicks deemed genuine after filtering	Input to scoring
`squashedClicks`	Normalized, manipulation-resistant counts	Input to scoring

A frequent point of confusion is the relationship between these signals and analytics metrics. NavBoost reads behavior from Google's own click logs and browser data, not from Google Analytics. Bounce rate as measured in GA4 is not a ranking input; the behavior it can proxy, returning to the SERP, is what NavBoost captures as a badClick. Keeping that distinction precise matters when interpreting any claim that "engagement metrics" influence ranking.

Frequently Asked Questions

What is the difference between NavBoost and Glue?

NavBoost is the click-based re-ranking system applied to the traditional organic web results, the ten blue links. Glue is the parallel system that applies click and interaction signals to all other SERP features, including featured snippets, knowledge panels, image packs, and video carousels. Pandu Nayak testified that both have operated since at least 2005.

What are goodClicks, badClicks, and lastLongestClicks?

They are three click classifications revealed in the 2024 Google API leak. A goodClick is a click where the user stays on the result, signaling satisfaction. A badClick is a click where the user quickly returns to the SERP, signaling dissatisfaction, also known as pogo-sticking. A lastLongestClick is the final, longest-dwell click in a session and is considered the strongest positive signal.

Is click-through rate a direct Google ranking factor?

Click-through rate is an input to NavBoost rather than a standalone ranking factor that operates in isolation. Post-click behavior such as dwell time and pogo-sticking carries at least as much weight. A high CTR that leads to badClicks can be worse than a moderate CTR with strong satisfaction signals.

Does NavBoost use Google Analytics or bounce rate data?

No. Google has repeatedly stated it does not use Google Analytics or GA4 engagement data as a ranking input, and bounce rate as measured in analytics tools is not a ranking factor. The underlying behavior that bounce can proxy, namely returning to the SERP, is captured by NavBoost as badClicks through Google's own click logs, not through analytics software.

What is a Twiddler in Google's ranking system?

A Twiddler is a re-ranking function that adjusts results after the primary scoring algorithm produces an initial order. The 2024 leak indicated NavBoost operates as one such re-ranking layer alongside Twiddlers for freshness, quality, and diversity, which can boost, demote, or constrain results before the final SERP is assembled.