Adding schema did not raise AI citations in an Ahrefs study
Summary
Schema markup is common on the pages AI tools cite. Once Ahrefs compared pages that added it against similar pages that did not, the citation gain disappeared. The markup looks like a trait of well-run sites, not a cause of citations.
Keep adding structured data where it earns rich results in Google. Do not sell it as an AI visibility tactic, and test it against control pages before claiming it works on your site.
Adding JSON-LD structured data to a page did not measurably change how often ChatGPT or Google’s AI Mode cited it, according to an Ahrefs study published on 2026-05-11. In Google AI Overviews, pages that added schema lost slightly more citations than comparable pages that did not.
Ahrefs ran the study to check its own earlier finding. An analysis of 6 million URLs had shown that pages cited by AI were almost three times more likely to carry JSON-LD than pages that were not. Figures like that get passed around as proof that schema drives AI visibility. The Ahrefs authors named the problem with that reading: schema tends to sit on better-maintained sites, and those sites also publish stronger content, earn more links and rank well in regular search. The markup could be doing the work, or it could just be present on pages that get cited for other reasons.
How Ahrefs separated schema from everything else
Xibeijia Guan, who ran the analysis, pulled URLs cited in AI Overviews from Brand Radar, Ahrefs’ tool for tracking AI citations, and checked each one’s crawl history for a <script type="application/ld+json"> tag. She kept the 1,885 pages where that tag first appeared during the study period, which ran from August 2025 to March 2026. Those pages were matched against 4,000 control pages from other domains that had similar citation levels and never added JSON-LD. Citations were counted for 30 days before and after the markup appeared.
The control pages matter because the AI platforms were moving on their own. AI Overviews were citing less over this period and AI Mode was growing fast. Raw AI Mode citations on the schema pages rose 43%, which looks like a win until set against the controls, which gained almost as much.
Ahrefs trusts one test most: a difference-in-differences comparison, which measures the change on the schema pages against the change on the controls, so the platform-wide trend cancels out. It produced these results:
| Platform | Effect of adding schema | Ahrefs’ verdict |
|---|---|---|
| Google AI Overviews | -4.6% | Small but statistically significant decline |
| Google AI Mode | +2.4% | Indistinguishable from zero |
| ChatGPT | +2.2% | Indistinguishable from zero |
Three other checks pointed the same way. Ahrefs compared plain averages, plotted citations week by week, and reran the main test with a different time window.
The AI Overviews dip is not a penalty
The AI Overviews decline works out to about 12 fewer daily citations per page, on pages that mostly got hundreds. Both groups were already falling steeply before any schema went in, which Ahrefs attributes to AI Overviews pulling back from these kinds of content. Ahrefs says its data cannot tell whether the markup caused the extra drop or something else did. The likelier conclusion is that schema neither helped nor hurt in a way a site would notice.
What the study leaves open
The study is narrower than its headline, and a few gaps could hide a real effect:
- Format: only JSON-LD was tested. Microdata and RDFa were not.
- Schema type: all types were pooled, so one type that helps could be averaged away by the rest.
- JavaScript injection: schema added by JavaScript was not examined.
- Other changes: links or content updates made at the same time as the markup were not fully separated out.
None of these gaps touch the reason most sites add schema in the first place. Google’s documentation on structured data ties it to rich results and cites Rotten Tomatoes measuring a 25% higher click-through rate on pages with structured data. AI citations were never part of that case.
What to do
- Stop presenting schema as a lever for AI citations, in pitches or in audits. The evidence for it is a correlation that Ahrefs’ own matched test did not confirm.
- Keep adding structured data where Google offers a rich result for the page type. Our analysis of where schema pays off covers which types are worth the effort.
- Do not remove existing schema because of the AI Overviews dip. The effect is small and Ahrefs could not attribute it to the markup.
- If you believe a specific schema type matters for your pages, test it the way Ahrefs suggests. Pick 5–10 pages that already get AI citations and 5–10 control pages with similar citation levels. Record a baseline, add schema to the test pages only, and compare the two groups after 30 days or longer. A before-and-after check without controls will mostly measure what the platform did that month.