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Official statement

Google does not have any concept of LSI keywords. It's an interesting theoretical topic in computer science regarding information retrieval, but SEOs do not need to concern themselves with it in their practice.
555:58
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Extracted from a Google Search Central video

⏱ 912h44 💬 EN 📅 05/03/2021 ✂ 20 statements
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📅
Official statement from (5 years ago)
TL;DR

John Mueller states unequivocally: Google does not utilize any concept of LSI keywords in its ranking algorithm. This term, borrowed from theoretical information retrieval, has no practical relevance for SEOs. The obsession with 'semantically related keywords' identified by third-party tools stems from a misunderstanding of how the search engine actually operates.

What you need to understand

What is LSI and where does this confusion come from? <\/h3>

LSI (Latent Semantic Indexing)<\/strong> refers to a mathematical technique developed in the 1980s to analyze relationships between terms in large documentary corpuses. The idea: extract implicit semantic patterns by reducing the dimensionality of textual data through matrix decomposition.<\/p>

The problem? This method was never designed to index the web at the scale of Google. It remains too resource-intensive<\/strong> and unsuitable for real-time processing of billions of pages. Yet, part of the SEO ecosystem has recycled this term to sell tools purportedly designed to identify 'LSI keywords' — that is, semantically similar terms that must absolutely be included in content.<\/p>

Why is Google making this statement now? <\/h3>

Mueller responds to a recurring question within SEO communities, where the LSI myth still circulates. Some tools offer lists of 'LSI synonyms' or 'related terms' claiming to adhere to this theory. Google wishes to clarify: this is not how its engine works.<\/strong><\/p>

The confusion arises from a misunderstanding of how BERT, MUM, or RankBrain<\/strong> process natural language. These ML models do not rely on vintage LSI matrices, but on contextual embeddings and transformers that can grasp semantic nuances without going through this intermediary step.<\/p>

So how does Google really understand the meaning of content? <\/h3>

Google relies on pre-trained language models<\/strong> that capture semantic relationships directly from real contexts. These systems analyze not lists of theoretical synonyms, but how words articulate within complete sentences, according to their position, syntax, and natural co-occurrence.<\/p>

Specifically? There’s no need to stuff your page with 'LSI variants.' What matters is written quality, thematic coherence, and accurately addressing search intent<\/strong>. Modern algorithms can detect when there’s an artifice when terms are forcibly inserted to 'cover the semantic field' mechanically.<\/p>

  • LSI is not used by Google<\/strong> — it’s an academic technique unrelated to modern web indexing<\/li>
  • Tools that promise 'LSI keywords' are selling a chimera or, at best, lists of statistically correlated terms<\/li>
  • Google uses contextual language models (BERT, MUM) that have nothing to do with LSI<\/li>
  • Real semantic optimization requires editorial relevance, not a checklist of synonyms<\/li>
  • Focus on user intent and content fluency rather than pseudo-scientific formulas<\/li><\/ul>

SEO Expert opinion

Is this statement consistent with real-world observations? <\/h3>

Absolutely. A/B tests conducted on 'content enriched with LSI keywords' versus natural content show no measurable positive impact on rankings<\/strong>. Worse: pages that force the inclusion of unnatural terms sometimes show degraded engagement metrics (reading time, bounce rate), ultimately harming overall SEO.<\/p>

What we actually observe? Google values comprehensive coverage of a topic<\/strong>, but not through a list of imposed keywords. Content that addresses all facets of a search intent — with examples, data, logical structures — outperforms texts stuffed with forced synonyms. The difference is subtle but crucial: covering a topic ≠ checking vocabulary boxes.<\/p>

Why does this myth persist in the SEO industry? <\/h3>

Because it answers a need for a simple recipe<\/strong>. 'Add these 10 LSI keywords and your page will rise' — it's reassuring, measurable, and easy to sell. However, modern SEO does not work through mechanical checklists. Agencies and software publishers have a vested interest in promoting quantifiable methods, even when they rest on outdated theoretical foundations.<\/p>

There’s also a game of telephone going on: LSI was mentioned in old Google patents (which do not describe the algorithm in production), then recycled in blog articles, then turned into dogma. Result: a generation of SEOs firmly believes in a concept that Google never implemented on a large scale.<\/strong> [To be verified]<\/strong>: some claim that variations of LSI may have been tested in experimental versions of the algorithm — but no official source supports this.<\/p>

What nuances should be added to this statement? <\/h3>

Mueller says Google has 'no concept of LSI keywords.' This is strictly true: there is no singular value decomposition matrix running in the background. But Google does use vector representations of words and phrases<\/strong> (word embeddings, sentence embeddings) that capture semantic relationships.<\/p>

The nuance? These embeddings are not 'LSI keywords' that could be listed and integrated manually. They are contextually calculated vectors<\/strong>, which evolve according to the complete sentence, the document, the query. In other words: Google understands semantics, but not through the method that SEO tools claim to simulate. Let’s not confuse 'modern semantic analysis' with 'vintage LSI'.<\/p>

Practical impact and recommendations

What should you do concretely to optimize the semantics of your content? <\/h3>

Write for humans<\/strong>, not to feed an artificial semantic field. Google prefers fluent, structured text that precisely answers users' questions. If you delve into a topic deeply, relevant terms will naturally appear — there’s no need to force the insertion of 'LSI synonyms' identified by a third-party tool.<\/p>

Focus on search intent<\/strong>. Analyze the SERPs for your target: what angles are covered? What recurring questions? What formats dominate (guides, comparisons, definitions)? Then structure your content to provide a more complete, better-organized, more actionable response than the competition. It’s this editorial exhaustiveness that makes the difference, not a checklist of words.<\/p>

What mistakes should be avoided in semantic optimization? <\/h3>

Do not stuff your pages with terms 'recommended' by LSI tools. This practice generates disguised keyword stuffing<\/strong>, harms readability, and risks triggering quality filters (especially if the text becomes artificial). Google detects very well when content forces the insertion of unnatural variants just to 'cover the lexical field'.<\/p>

Avoid also paying for 'LSI' audits promising to identify your 'semantic gaps'. These analyses often compare your page to a corpus of competing content and suggest adding all the words they use — without consideration for real relevance or user intent<\/strong>. It’s a logic of blind mimetism that produces no differentiating value.<\/p>

How can I verify that my semantic approach is effective? <\/h3>

Test real engagement: reading time, scroll depth, bounce rates, conversions. Semantically relevant content retains attention<\/strong> because it provides concrete answers, not because it checks vocabulary boxes. If your UX metrics are good, it’s the most reliable signal that your semantics are working.<\/p>

Also, monitor long-tail queries for which you are starting to rank. Well-structured content around a topic naturally attracts traffic on related variants and questions — without having explicitly targeted these terms<\/strong>. This is proof that Google understands your topic in depth, far beyond simple keyword matching.<\/p>

  • Write exhaustive content that covers all facets of a topic, not just a list of synonyms<\/li>
  • Structure with logical Hn, short paragraphs, lists — clarity helps both algorithms and readers<\/li>
  • Ignore tools that promise 'LSI keywords' — instead, invest in intent analysis and competitive monitoring<\/li>
  • Measure impact through user engagement (time, scroll, conversions), not through a checklist of checked terms<\/li>
  • Test editorial variations (angle, depth, format) and observe what actually performs in SERPs<\/li>
  • Prioritize writing quality and precise responses to intent rather than mechanical optimization<\/li><\/ul>
    Modern semantic optimization relies on a fine understanding of user intent and the production of comprehensive, structured, engaging content. Shortcuts like 'LSI keywords' are not only ineffective, but can also harm the quality perceived by Google and visitors. If these adjustments seem complex to manage internally — particularly large-scale intent analysis, thorough competitive auditing, or complete editorial overhauls — assistance from a specialized SEO agency can accelerate implementation and secure long-term results.<\/div>

❓ Frequently Asked Questions

Les outils qui proposent des mots-clés LSI sont-ils complètement inutiles ?
Ils peuvent identifier des termes corrélés statistiquement, mais ce n'est pas du LSI au sens strict, et Google ne fonctionne pas ainsi. Utilisez-les comme source d'inspiration thématique, pas comme checklist à cocher mécaniquement.
Google utilise-t-il d'autres techniques pour comprendre la sémantique d'un contenu ?
Oui : BERT, MUM, RankBrain et d'autres modèles de langage contextuels analysent les relations entre mots en fonction du contexte réel, pas via des matrices LSI vintage.
Faut-il quand même varier le vocabulaire dans mes contenus ?
Oui, mais naturellement. Utilisez des synonymes et tournures variées pour améliorer la lisibilité et couvrir le sujet en profondeur, pas pour « optimiser LSI ».
Cette déclaration de Mueller change-t-elle quelque chose à ma stratégie SEO ?
Si vous forciez l'insertion de termes LSI, oui : arrêtez. Concentrez-vous sur l'intention utilisateur, la structure, la profondeur éditoriale. Si vous écriviez déjà naturellement, rien ne change.
Peut-on encore se fier aux anciens brevets Google mentionnant LSI ?
Les brevets décrivent des pistes de R&D, pas forcément l'algo en production. Google a clairement indiqué que LSI n'est pas utilisé — fiez-vous aux déclarations officielles récentes, pas aux brevets vintage.

🎥 From the same video 19

Other SEO insights extracted from this same Google Search Central video · duration 912h44 · published on 05/03/2021

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