In short: In the largest controlled test to date, adding schema markup produced no citation gains in AI engines: statistically insignificant moves for ChatGPT and Google AI Mode, and a significant decline for Google AI Overviews. Every page studied was already heavily cited, so this measures marginal returns for established pages, not first-time citation. Schema still earns Google rich results, so keep it – just do not expect it to buy AI citations.
“Add schema markup to get cited by AI” is one of the most repeated pieces of AEO advice. It is also, on the best available evidence, wrong. The confusion is understandable: pages with schema do tend to get cited more often. But that correlation tracks overall site quality, not the markup itself, and when you isolate the markup in a controlled test, the effect disappears.
What the study actually did
Ahrefs ran a difference-in-differences test: they took 1,885 pages that added JSON-LD structured data and compared their change in AI citations against 4,000 matched control pages that did not. The results were mixed and none supported the “schema wins citations” story: ChatGPT and Google AI Mode moved a couple of percentage points, both statistically insignificant, while Google AI Overviews showed a statistically significant decline of about 4.6% – the opposite of the hypothesis. The design matters here: by matching controls and measuring the change around the schema addition, the test separates the markup’s effect from the general “better sites have schema and also get cited more” confound that makes raw correlations misleading.
One caveat cuts both ways and is worth stating plainly. Every page in the sample was already heavily cited before the test – 100 or more AI Overview citations each. So the study measures whether schema lifts pages that are already winning, not whether it helps a brand-new page get cited for the first time. That second question is still open. What the evidence rules out is treating schema as a reliable lever for more AI citations on established content.
Why this result is plausible
Large language models are trained on and retrieve from rendered text, not primarily from a page’s JSON-LD block. The signals that do move AI citations are about the visible content. A controlled experiment across 10,000 queries, the Generative Engine Optimization paper (KDD 2024), found that named quotes, sourced statistics, and inline citations produced double-digit visibility gains in AI answers. Those live in the prose a model reads, not in markup a model largely ignores.
So should you still add schema?
Yes – for the reason schema has always been worth adding. Structured data drives Google rich results: review stars, FAQ accordions, breadcrumb trails, sitelinks. That value is well-established and independent of anything to do with AI citations. The honest framing is simple: ship schema for rich results, and do not count it as an AI-visibility tactic. Anyone selling structured data as the way to get cited by ChatGPT is overstating a case the controlled evidence does not support.
This is the pattern worth internalizing across AEO advice: separate what is measured from what is repeated. We keep a running evidence ranking that labels each tactic strong, moderate, or weak with the study behind it, precisely so schema-style myths do not become load-bearing in a content strategy.
Frequently asked questions
Does schema markup help SEO at all?
Yes, for rich results in traditional Google search – star ratings, FAQ accordions, breadcrumbs, and similar enhancements. That benefit is well-established. The finding here is narrower: schema does not measurably increase citations in AI answer engines.
If schema does not help AI citations, what does?
Named statistics with sources, expert quotes, inline citations, server-rendered content that AI crawlers can actually read, and freshness. These are the tactics with controlled evidence behind them.
Should I remove schema from my pages?
No. Keep it for Google rich results. Just do not expect it to influence whether AI engines cite you, and do not prioritize it over the content-level signals that do.
Written by Shivaa Tripathi, who has spent 12+ years in B2B marketing and builds organic-os, an open-source organic-growth plugin. Sources are linked inline; the full evidence ranking is on the What works page.
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