Keep your prose readable so AI summaries stay faithful to your meaning
Median Flesch Reading Ease at fifty or above, grade level twelve to fourteen depending on audience.
What this signal tests
We compute two well-known readability scores over your main content: Flesch Reading Ease and Flesch-Kincaid Grade Level. We expect the median Reading Ease across the page to be at least 50, and the median Grade Level to be at most 12 for marketing or landing content, or at most 14 for technical documentation. The scores are calculated over sliding 200-word windows of your content.
Why it matters for your visibility in AI
Readability scores correlate with how cleanly AI systems summarize and embed your prose. Long, multi-clause sentences with rare vocabulary produce noisier embeddings - the model is less confident about what the passage means, and similar queries match less reliably. Summaries of complex prose drift further from the source meaning. The same content, rewritten at a lower grade level, generates tighter embeddings and more faithful summaries. The concrete consequence is that an AI assistant asked to explain a topic you wrote about may produce a summary that subtly misrepresents your stance, simply because the model lost confidence parsing your sentences. Plain language is not dumbing-down; it is widening the bandwidth between your meaning and the model's representation of it.
Pass criteria at a glance
| Criterion | Passes when |
|---|---|
| Median FRE >=50 AND median FKGL <=12 (marketing) or <=14 (technical). |
How we test it
We extract the page's main content (using the same heuristics as the boilerplate-ratio check), then slide a 200-word window across the text and compute Flesch Reading Ease and Flesch-Kincaid Grade Level for each window. We aggregate to a median per metric. The page passes when the median Reading Ease is at least 50 and the median Grade Level is at most 12 for marketing pages, or at most 14 for technical documentation.
Show technical detection method
Extract main content; compute FRE and FKGL over 200-word sliding windows; aggregate median.
If your site fails: how to fix it
- Shorten sentences to twenty words or fewer where possible; split multi-clause sentences at conjunctions, since sentence length is the single biggest driver of both scores.
- Prefer common words over jargon when both convey the same meaning - "use" beats "utilize", "start" beats "commence" - without losing precision.
- For unavoidably technical passages, add a one-sentence plain-language summary at the top of the section that captures the gist for both human skimmers and AI summarizers.
- Replace nominalized verbs ("the implementation of the feature") with active forms ("implementing the feature"); active voice typically scores better on both metrics.
- Use a readability checker (the readable.com, Hemingway, or a CMS plugin) on draft content before publishing so issues are visible during writing rather than after the fact.
Quick facts
| Maturity | ESTABLISHED |
|---|---|
| Weight | medium |
| Category | Content Clarity |
Primary sources
Related signals
No related signals listed.
Frequently asked questions
Will dumbing down my content hurt my expertise signal?
Plain language and expertise are independent. Top-rated technical writers - and the best documentation on the web - score well on readability while remaining authoritative. The score rewards clarity, not simplicity of subject. Complex ideas can be explained simply; that is the goal.
Are these scores AI-specific or also classic SEO?
They originated in classic readability research and are referenced by WCAG accessibility guidelines. AI ingestion benefits from the same properties - short sentences, common vocabulary - because they reduce ambiguity for the model. The metrics are shared; the consequences of failing them differ between domains.
What if my audience is technical specialists?
Technical documentation has a higher allowable grade level (up to 14) for exactly this reason. The goal is not to write for a general audience always, but to avoid sentence structure and word choice that obscures meaning regardless of audience. Specialists still benefit from clarity.
How fresh does my content need to be in terms of style?
This signal is about prose complexity, not freshness in the temporal sense. Old, well-written content scores well; recent, convoluted prose scores poorly. Style updates do not need to be frequent - once your content reads cleanly, it tends to stay that way unless someone rewrites it.
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