There’s a rule of thumb I’ve started including in every AEO audit I deliver, and it’s the one that tends to produce the fastest results when clients act on it: the 40-Word Rule.
The underlying data: AI extraction systems pull answers under 40 words at more than twice the rate they extract longer passages. The reason isn’t arbitrary — it’s about how retrieval-augmented generation pipelines evaluate content for citation suitability.
Let me explain the mechanism, and then show you what this looks like in practice.
Why 40 Words?
When an AI system is synthesizing an answer to a user’s question, it’s not reading your entire blog post and summarizing it. It’s scanning for an extractable unit — a chunk of text that directly answers a specific question, is factually dense, and is short enough to reproduce without paraphrase.
Think of it like a quotation. When a journalist quotes a source, they quote the most precise, direct statement available — not a paragraph that eventually gets to the point. AI systems operate similarly. They’re looking for the sentence or two that is the answer, not the paragraph that builds up to it.
40 words is roughly two sentences. Two sentences is enough to answer most questions directly and completely, if you write with precision.
What This Looks Like in Practice
Here’s an example of the same information written two ways:
The version most websites have: ‘Answer Engine Optimization is a relatively new discipline in the digital marketing space that has emerged in response to the growing prevalence of AI-powered search tools and the changing behaviors of users who increasingly expect to receive direct answers to their questions rather than a list of links they need to click through to find information.’
That’s 61 words. It meanders. It builds context before delivering the point. AI systems frequently skip content structured this way.
The AEO-optimized version: ‘Answer Engine Optimization is the practice of structuring content so AI systems like ChatGPT and Perplexity extract, cite, and present it as a direct answer. It differs from SEO in that it targets AI citation, not search engine ranking.’
That’s 39 words across two sentences. It leads with the direct answer. It differentiates in the second sentence. It’s extractable.
Same information. Completely different extraction probability.
How to Apply the 40-Word Rule to Your Content
You don’t need to rewrite your entire site. You need to add answer blocks — short, direct responses to the question each section promises to answer — at the top of each major content section.
Think of it as a lead sentence for every H2. Before you build out the full explanation, give the AI (and the human reader) the direct answer in two sentences or fewer. Then expand into your full explanation for the readers who want depth.
This structure serves both audiences: the AI extracts the lead block, and the human reader gets the full context. Nobody loses.
Combining the 40-Word Rule with FAQ Schema
The most powerful AEO content structure combines the 40-Word Rule with FAQPage schema. Each FAQ question gets a schema-marked answer that is 40 words or fewer. The AI can identify it as a question-answer pair through the schema, and extract the answer directly because it’s concise.
This is the foundation of what I look for in an AEO audit. Pages that do both — FAQ schema with concise answer blocks — consistently outperform pages that do one or neither. The combination is more than additive; it’s how you tell the AI system exactly what to take and how to use it.
If you do nothing else this week for your AEO, go to your most important page and add a 40-word answer block at the top. It’s the smallest change with the largest extraction impact I know of.