Information Gain

What information gain means in SEO and AI search — how Google's Information Gain Score patent works, why original research and unique data outperform regurgitated content, and how to measure it.

First published: Jul 2, 2026 · Last updated: Jul 18, 2026 · Advanced
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Information gain is how much *new* information your page adds beyond what a searcher has already seen in the results for a topic — novelty relative to the existing corpus, not general content quality. The term comes from a real Google patent ('Contextual estimation of link information gain,' filed 2018, granted 2022) that scores documents 0.00–1.00 for novelty and ranks partly on that score — but Google has never confirmed using it in live ranking, and the patent's framing is about what to show *next* after a user has seen some results, not the first page. There's no visible score in Search Console, no API, and no public formula: any 'information gain score' in a tool is an approximation. What's real and official is Google's helpful-content guidance asking whether content offers 'original information, reporting, research, or analysis.' It matters more now because AI Overviews and AI Mode can already synthesize consensus content — only genuinely new information (proprietary data, original research, first-hand expertise) is what AI has to cite instead of absorb.

TL;DR — Information gainInformation gain is how much new information a page adds beyond what a searcher has already seen in prior results on the same topic — novelty relative to the existing corpus, not general content quality. The term comes from a granted Google patent that Google has never confirmed using in live ranking. is novelty relative to the corpus a searcher has already seen on a topic — not comprehensiveness, not E-E-A-T, not “quality” in the abstract. It’s named after a granted Google patent (“Contextual estimation of link information gain,” filed 2018, granted 2022) that scores documents 0.00–1.00 for how much new information they add and ranks partly on that. But: Google has never confirmed live use; the patent’s own framing is about what to show next after a user has seen some results, not the first page; and there’s no visible score, no API, no disclosed formula. What is official is Google’s helpful-content guidance asking for “original information, reporting, research, or analysis.” It matters more in an AI-answer SERP because LLMsA large language model (LLM) is a deep-learning model trained on massive text corpora to predict the next token and generate human-like text. LLMs use the transformer architecture and power AI search features like Google's AI Overviews (Gemini) and Bing Copilot (GPT-4). synthesize consensus for free — only genuinely new information forces a citation.

What information gain actually is (and isn’t)

The cited patent describes possible methods, not proof that a specific production ranking system operates exactly that way. Evidence for this claim Official or primary documentation supporting the adjacent article claim, with scope limited to the source's published description. Scope: No ranking guarantee or undisclosed system mechanics are inferred beyond the cited source. Confidence: high · Verified: Google patent: Contextual estimation of link information gain Use original-value guidance as an editorial principle, not a measurable ranking guarantee. Evidence for this claim Official or primary documentation supporting the adjacent article claim, with scope limited to the source's published description. Scope: No ranking guarantee or undisclosed system mechanics are inferred beyond the cited source. Confidence: high · Verified: Google: Helpful content guidance

Most articles on this topic quietly conflate three different things. Keep them separate:

  • Information gain — the marginal new information a document adds relative to what the searcher has already seen on the topic. It’s a delta.

  • Comprehensiveness / topical depth — covering everything about a topic. A page can be maximally comprehensive and have zero information gain if every fact in it already exists on the pages ranking above it.

  • E-E-A-T / content quality — trust, expertise, experience, authority. Related, but a different judgment. You can be an unimpeachable expert and still publish a page that adds nothing new.

  • Truth and accuracy — being novel isn’t the same as being correct. A page can add a genuinely new claim and still get it wrong. Novelty, accuracy, and trust are separate judgments; treat originality as one input to publish, not a substitute for verifying it.

If you take one thing from this page: information gain is specifically about the delta, not the depth and not the trust. That distinction is the thing nearly every competing explainer blurs.

One more distinction worth naming, because SEO borrowed the term loosely: “information gain” also has an older, more technical meaning outside search. In information theory it traces back to Claude Shannon’s 1948 work on entropy and information measures — a mathematical account of how much a signal reduces uncertainty, unrelated to search rankings. In information retrieval research, a parallel idea shows up as novelty and diversity: methods like Maximal Marginal Relevance (Carbonell and Goldstein, 1998) rerank or select results to reduce redundancy against what a reader has already seen. Google’s patent draws on the same underlying intuition — new relative to what’s already been shown — but none of these are interchangeable. The SEO industry’s “information gain” is shorthand built on a specific patent, not a direct application of Shannon’s math or of published IR diversity algorithms, even though the instinct they share (don’t just repeat what’s already there) rhymes across all three.

Information gain is the delta beyond what was already available—not the total length or polish of the candidate page. Source: /ai-search/optimization/information-gain/

The top box represents consensus facts A, B, and C that the reader has already seen. The low-gain candidate repeats A, B, and C in different wording. The high-gain candidate adds original evidence D that was absent from the earlier sources. The comparison is conceptual, not a confirmed ranking factor or public Google score.

© Patrick Stox LLC · CC BY 4.0 ·

The Google patent behind the term

What it says

The patent is “Contextual estimation of link information gain” (US20200349181A1, filed October 2018, granted June 2022; inventors include Victor Carbune and Pedro Gonnet Anders). The core definition, verbatim from the patent:

“An information gain score for a given document is indicative of additional information that is included in the given document beyond information contained in other documents that were already presented to the user.”

It describes a machine-learning model that takes semantic vectors from documents the user already viewed plus data from a candidate new document, and outputs, in the patent’s words:

“a quantitative score between 0.00 and 1.00, with 0.00 indicating that no information gain is to be expected”

— with 1.00 meaning the document contains only information not in what was already seen. Documents may then be ranked at least partly on their respective information gain scores.

What it doesn’t say

This is where most SEO content overreaches, so let me be precise about the limits:

  • No confirmed live use. A granted patent is evidence Google could deploy this, not that it does. Google has not confirmed or denied using this mechanism in ranking. Anyone telling you it’s a confirmed ranking factor is guessing.
  • Narrower scope than assumed. The patent’s framing centers on choosing what document or link to surface next — think a conversational or assistant follow-up after a user has already viewed some results — not on the first page of ten blue links. Roger Montti’s analysis at Search Engine Journal makes this scope point well: the emphasis is on automated assistants, and these scores aren’t described as applying to the first set of results (SEJ).
  • No public formula. The patent names “semantic vectors” and salient extracted information, but discloses no weights, no feature list, and no reproducible scoring method. Do not trust any article that hands you a precise “how Google calculates it” formula — it’s invented.
  • It’s a patent family, not one filing. Google was granted a continuation in the same family — US12013887B2, same title, same assignee (Google LLC), priority date back to the original October 2018 filing. A continuation means more disclosed claim language exists in the family, not that anything new about deployment has been confirmed — a granted patent and its continuation still only establish what Google disclosed it could build, not what’s running in production.

Bill Slawski’s early breakdown at Go Fish Digital framed the underlying problem Google is solving — that when many documents share a topic, they tend to contain similar information — and how the patent proposes ranking partly on information gain scores to address it (Go Fish Digital).

Google’s official guidance that echoes the idea

Here’s the honest part most explainers skip: no Google document, blog post, or spokesperson uses the phrase “information gain” in public search guidance. The term is industry shorthand. But Google’s actual official guidance — “Creating helpful, reliable, people-first content” — repeatedly describes the same underlying idea in its self-assessment questions. These are verbatim from that page:

“Does the content provide original information, reporting, research, or analysis?”

“If the content draws on other sources, does it avoid simply copying or rewriting those sources, and instead provide substantial additional value and originality?”

“Does the content provide insightful analysis or interesting information that is beyond the obvious?”

“Does the content provide substantial value when compared to other pages in search results?”

That last one — substantial value compared to other pages in search results — is about as close as Google’s official language gets to the information-gain concept without using the term. This is the strongest legitimately-official tie-in available, and it’s why “information gain” caught on as useful shorthand for a real principle Google clearly cares about, even though it’s not Google’s word.

Does Bing use information gain?

Not that I’ve foundA 302 (\"Found\") is a temporary redirect: it forwards users to a new URL while telling search engines the original URL should stay in the index. It's a weak canonicalization signal, not the zero-equity dead end of SEO folklore.. No Bing or Microsoft document or spokesperson uses the term in the material I’ve reviewed. Bing’s publicly discussed ranking factors — site and author reputation, content completeness, semantic relevance — point in a similar direction (depth and originality versus peers), but that’s an adjacent idea, not the same claim and not the same vocabulary. If someone quotes Bing using the literal phrase “information gain,” treat it with suspicion until you see the primary source.

Why information gain matters more in an AI-answer-heavy SERP

This is the part that makes information gain more than a patent-trivia curiosity.

AI has read the internet. ChatGPT, Claude, Gemini, and Google’s own AI OverviewsAI Overviews are the AI-generated summary box Google shows above or within its regular search results, written by Gemini models from pages retrieved out of Google's normal Search index. It's a Search feature, not a separate platform or index. and AI Mode are excellent at one specific thing: synthesizing and repackaging what already exists across the web. Nathan Wahl at Animalz makes the argument sharply — these systems can already reiterate and repackage everything that’s been published, so the question becomes why publish anything that isn’t additive. When Google synthesizes an answer, it pulls from multiple sources — Wahl’s framing is that you don’t need to outrank giants if your content contains information theirs doesn’t (Animalz).

That’s the mechanism. If your page restates consensus, an AI Overview absorbs it and answers without sending anyone to you. If your page contains something only you have — a proprietary number, a real experiment, an expert’s first-hand take — an AI system has to draw on you specifically to include that fact, rather than paraphrasing it from wherever else it appears. That’s not a guarantee: retrieval, inclusion in the model’s context, generation, and citation are separate steps, and originality clearing one of them doesn’t mean it clears the rest. Scoped research on generative-engine visibility (Aggarwal et al., “GEO: Generative Engine Optimization”) finds that adding sources, statistics, and quotations to content can improve visibility in AILLM visibility (or AI visibility) is the aggregate measure of how often and how prominently a brand or page shows up in AI-generated answers — across AI Overviews, ChatGPT, Perplexity, Copilot, and Gemini. It's the AI-search analog of organic visibility, but it's driven by different signals.-generated answers in their tested setups — evidence that originality helps, not proof that it guarantees a citation, a ranking, or traffic. Information gain is a precondition for being cited instead of paraphrased, not a promise of it.

Bernard Huang at Clearscope has tied this to Google’s Knowledge GraphThe Knowledge Graph is Google's database of entities — people, places, organizations, and things — and the factual relationships between them. It's separate from any single website's structured data: your schema markup is one of many possible inputs to the graph, not the graph itself.: aim for content that covers concepts and entities on the fringe of what Google already “knows” about a topic, because LLMs are great at consensus but genuine novelty is still where humans add value (Clearscope). Amanda King’s early Search Engine Land framing captured the core idea — an information gain score is essentially a measure of how unique your content is versus the rest of the corpus, and content risks being demoted if it lacks uniqueness even when it’s just the same ideas in different words (Search Engine Land). Andrew Holland later reframed the whole thing for the AI era: the term means different things to different people, but the job is to keep increasing the rate of information gain — and increasingly we’re optimizing for AI, not just for Google (Search Engine Land).

I’ve seen this from the other direction, too. I ran some tests trying to rank content in Google’s AI Mode, and the content simply didn’t rank — even though it was, as far as I could tell, better and more relevant than pages that did. One of the possibilities I floated publicly was a lack of information gain in the articles: if the content is a well-written restatement of what’s already out there, there may be nothing for the system to reward (my post on X).

What actually produces information gain

Synthesizing across the sources — and my own experience — here’s what genuinely moves the needle:

  • Original research, surveys, and experiments. The most defensible form. Run a study, publish the data, let others cite you. At Ahrefs, our best-performing content skews heavily toward data studies for exactly this reason.
  • Proprietary / first-party data. Internal product or usage data nobody else can reproduce. If you have a dataset, that dataset is your information gain.
  • Expert interviews and first-hand experience. This is my go-to tactic. Rather than shipping unsourced generated text, message a handful of real subject-matter experts you already have access to — over Slack, email, or a quick AI-assisted call — a few times a week, and capture their actual stories and experience. That’s original information that didn’t exist on the web before you published it. I applied this to my own rebuild of Ahrefs’ technical SEOTechnical SEO is the practice of making a site easy for search engines to crawl, render, index, and (now) be eligible for AI answers. It's the foundation that lets your content and links rank — not a ranking trick of its own. hub (roughly 160 AI-generated pages) by layering expert review and reader feedback on top so the pages carry something beyond regurgitated consensus.
  • Contrarian or updated takes on consensus. Testing a widely repeated claim and reporting what actually happened is information gain, even when the “study” is small.
  • Building on a predecessor’s work. Take someone’s published research, extend it, add the next data point. You’re adding to the corpus, not copying it.

Ahrefs’ own content-quality ladder (Si Quan Ong’s “How to Create Quality Content”) is a useful map here: it climbs from simple listicles up to research studies and original ideas — effectively an information-gain ladder, prizing first-hand data over aggregation, without ever using the term.

How to evaluate your own content for information gain

Adapt Google’s helpful-content questions into a pre-publish gut check:

  • Open the top results for your target query. List what each one already says.
  • For your draft, highlight every sentence that adds a fact, number, angle, or experience not on that list. If nothing is highlighted, you have a rewrite, not a resource.
  • Ask whether an AI could answer the query fully from the pages already ranking. If yes, your only path to relevance is contributing something those pages lack.
  • Sanity-check the “value compared to other pages in search results” question literally — not “is this good,” but “is this additive.”

The bottom line

Information gain is a real, useful concept sitting on top of an unconfirmed mechanism. Don’t sell it internally as a confirmed Google ranking factor with a score you can dial — that’s not true, and it’ll burn your credibility. Sell it as the thing that’s demonstrably working in an AI-heavy SERP: stop publishing better-optimized versions of what already exists, and start publishing what only you can. That’s the moat.

Related reading in this cluster: entity SEOEntity SEO is the practice of helping search engines and AI systems clearly identify, classify, and trust the entities you represent — your brand, your people, your products — rather than just matching keyword strings. The goal is to be an unambiguous, well-corroborated entity in machine knowledge systems so AI can cite you with confidence., schema markup for AISchema markup (structured data) is machine-readable code — usually JSON-LD — that labels what your content means using the schema.org vocabulary. For AI search it's infrastructure for entity disambiguation, not a direct citation lever: controlled studies found no meaningful uplift in AI citations from adding it., GEOGenerative Engine Optimization (GEO) is the practice of optimizing content and brand presence so AI-powered search engines and assistants — Google AI Overviews, ChatGPT, Perplexity — cite, recommend, or mention you when generating answers. Google's position is that it's still SEO., and AEOAnswer Engine Optimization (AEO) is the practice of structuring content so engines deliver it as a direct answer — featured snippets, voice assistants, and AI search — rather than just a ranked link. Coined for voice search in 2018 and revived for the LLM era. Google's position is that it's still SEO. all connect to how you get surfaced and cited once your content actually has something new to say.

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