Publishers are seeing a per-query clickthrough rate loss of almost 50% when AI Overviews appears, according to a new study.
The research, by AI search and SEO platform Authoritas, measures the impact of AI Overviews on UK publishers’ web traffic, assessing the clickthrough decline across both mobile and desktop.
The findings have been submitted as part of a legal complaint to the UK’s competition watchdog Competition and Markets Authority (CMA) about the impact of Google AI Overviews on news publishers.
When AI Overviews is present, publishers witness a drop of 47.5% in clickthrough rate on desktop, and 37.7% on mobile.
The data was collected using a set of news keywords and phrases reflecting news stories published by UK mainstream publishers between 16-22 April 2025.
A Google spokesperson told The Guardian the study was “inaccurate and based on flawed assumptions and analysis”, using outdated estimations and a set of searches that did not represent all the queries that would generate traffic for news websites.
“People are gravitating to AI-powered experiences, and AI features in search enable people to ask even more questions, creating new opportunities for websites to be discovered,” said the spokesperson.
“We continue to send billions of clicks to websites every day, and we have not seen dramatic drops in aggregate web traffic as is being suggested.”
AI Overviews penetration similar on desktop and mobile
Results for AI penetration – whereby AI Overviews appeared for keywords and phrases – were similar for both mobile and desktop: 426 of 3,500 search terms returned AI Overviews on desktop, and 427 of these returned AI Overviews on mobile.
These results led to the conclusion that AI Overviews penetration on both devices is at an average of 12.2%.
However, this varies depending on the keywords searched relating to news stories – for example, ‘health’ and ‘horoscope’ have 50% AI Overviews penetration.
Meanwhile, 12.5% of keywords relating to ‘current specific news stories’ brought up an AI Overview, according to the study. In May Google vice president of news partnerships Jaffer Zaidi said AI Overviews are purposefully not triggered for hard news queries.
‘Old specific news stories’, defined as those made on or before May 2024, were found to have a 30.3% AI Overviews penetration.
From this, the report concluded that once a news story has been on the web for a certain period of time, it seems more likely it will be summarised by an AI Overviews.
A dominance in domains was also found in AI Overviews, specifically with Google “favouring its own property”.
Links to Youtube (owned by Google’s parent company Alphabet) were more prominent compared with the normal search result system.
Situation to get ‘worse’ with AI Mode
It is also noted large scale research has not been carried out on Google’s new AI search experience, AI Mode. This recently launched in the US, and began rolling out in the UK on Tuesday.
“The situation will be even worse if [AI Mode] launches in the UK,” the report said, “as Google is using generative AI to answer almost every user question and follow-up question in AI Mode [in the US].”
The report also found, using Google Search Console data, that clickthrough rates on search engine results pages with AI Overviews are “considerably lower” than those without AI Overviews enabled, a result widely reported by other publishers but disputed by Google.
[Read more: Google AI Overviews leads to dramatic reduction in clickthroughs for Mail Online]
“Even if a site happens to rank in the top AI Overviews position, there is only a minor improvement in clicks and it is still considerably lower than search engine results pages without AI Overviews at all,” the report said.
This is “almost certainly” due to the ‘zero-click’ search effect, where a user feels satisfied with the AI summary and does not click through to the original publisher’s site.
“Given that Google has so far refused to share detailed data which would allow publishers to assess this themselves, we have to use estimates based on generally accepted industry principals and methods,” the report said.
These principles include items at the top of the list garner more attention and clicks.
AI Overviews for ‘more than 90%’ of queries feasible
Manual experimentation with Google’s Gemini chatbot and AI Mode while in beta in the US, as well as tracking changes to AI Overviews since its 2024 launch, led to the Authoritas report concluding “it is highly likely that the AI Overview penetration will increase in all international markets in the future”.
“It is also feasible that Google could return AI Overviews for more than 90% of queries if it chose to do so.”
The CMA has said it plans to give publishers more control over how their content appears in Google, which may include letting them opt out of AI Overviews without disadvantaging their other search referrals.
The legal complaint to the CMA, which the report contributed to, said publishers “urgently” need the ability to opt out of AI Overviews without being barred from normal search results pages.
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