A 1,100-person randomized experiment from UPenn and Northeastern confirms Google AI Mode slashes external clicks without improving user experience. Here is what service businesses must do now.
Ido Cohen · Published 2026-10-07 · SEO & Search
A peer-reviewed field experiment just put a hard number on what service business owners have suspected for months: Google's AI Mode reduces the share of searches that end with a click to an outside website by 18.8 percentage points — and users don't even like it. If your plumbing company, dental practice, law firm, or HVAC operation depends on Google search traffic to fill its pipeline, this study is the most important thing you'll read this week.
Researchers from the University of Pennsylvania and Northeastern University ran a preregistered randomized field experiment with 1,100 real Google users, published to arXiv in August 2026 and now circulating widely across Search Engine Land, Search Engine Journal, TechWyse, and MarketingProfs. The conclusion is blunt: AI Mode keeps people inside Google's walled garden and sends them to your website less often — all while making them less satisfied with Search in the process.
This isn't an opinion piece or a cherry-picked anecdote. It's a randomized controlled experiment — the gold standard for establishing cause and effect. According to coverage in Search Engine Land and Search Engine Journal, researchers from the University of Pennsylvania and Northeastern University published AI in Search Reduces Publisher Referrals Without Improving User Experience: Experimental Evidence, a preregistered field experiment that recruited 1,100 U.S.-based adults who used Google Chrome as their primary browser.
Here's what the data showed:
That last number is the kicker. Removing AI Overviews — Google's briefer AI summaries that show up in standard Search results — actually sent more people to external websites, with no measurable decline in how satisfied users said they felt about the search experience. Forced AI Mode, on the other hand, reduced trust, usefulness, satisfaction, and perceived personal relevance, with especially strong effects among heavy Google users.
The study also found that participants assigned to AI Mode were more likely to switch to competing search engines like Bing, DuckDuckGo, and Yahoo. Google is literally training its power users to leave.
Most of the coverage of this study focuses on media publishers — Variety, Rolling Stone, Wikipedia. But the implications for service businesses are just as severe, arguably more so, because service businesses operate on thin lead margins where losing even a handful of inbound calls per month can mean the difference between hitting payroll and missing it.
Here's what the math looks like at the local level. Suppose your HVAC company's website generates 400 organic visits per month from Google. A sustained 18.8-point reduction in click-through rates doesn't mean you lose 18.8 visits — it means that 18.8% fewer of the searches where you appear will result in someone actually landing on your site. Depending on your category and how often AI Overviews or AI Mode answers your queries, real traffic losses can compound quickly.
Service businesses face a compounding problem that media publishers don't:
1. Intent is high but patience is low. Someone searching "emergency plumber near me at 11pm" needs a phone number, not a 400-word AI summary. But if AI Mode intercepts that query and synthesizes a generic answer, they may never click through to your site.
2. You can't license your way out. Media companies like Penske (Variety, Rolling Stone) are exploring AI content licensing deals with Google. A 12-person HVAC company has no leverage to do that.
3. Reviews and local packs are partially insulated — for now. The Local Services Ads unit and the map pack sit outside the pure AI Mode experience, which is why paid local visibility has never been more important. But the study data is a warning shot: AI Mode is expanding, not contracting.
Google pushed back on earlier click-decline studies with language like "this study uses a flawed methodology and skewed queryset that is not representative of Search traffic." The company consistently argues that AI features create "new opportunities for people to connect with websites" and that it "consistently directs billions of clicks to websites daily."
That may be technically true in aggregate. But it sidesteps the core issue: individual businesses are experiencing traffic losses even if total search volume is rising. The UPenn/Northeastern experiment is a randomized controlled trial — not a correlation study, not a keyword sample. When researchers forced users into AI Mode and measured what happened next, click-through rates fell sharply and user satisfaction followed. That methodology is much harder to dismiss with "flawed queryset" language.
There's also a regulatory thread worth watching. According to Seafoam Media's October 2026 marketing roundup, the UK's Competition and Markets Authority has given Google until March 2027 to add page-level controls, and regulators expect click-through data to be included too. The CMA pressure suggests even governments are unconvinced by Google's "more traffic than ever" narrative.
Meanwhile, a US District Judge dismissed Penske Media Corporation's antitrust lawsuit against Google over AI Overviews traffic losses, ruling that no formal bargain had ever been struck between publishers and Google — so don't count on the courts to fix this for you. The regulatory and legal cavalry is moving slowly. Your marketing strategy needs to adapt now.
It helps to separate the permanent shift from the temporary turbulence.
What has genuinely changed:
What hasn't changed:
The takeaway: the more generic the informational query ("how much does HVAC installation cost?"), the more AI Mode hurts your organic visibility. The more local and transactional the query ("HVAC installation company in Austin"), the more your map pack and GBP matter.
Here's the part most SEOs are missing: the study also confirmed that appearing as a cited source inside an AI Overview or AI Mode answer carries higher click-through rates than appearing only in standard organic results — a finding echoed by Google's own CEO Sundar Pichai.
This is the new game for service businesses. The question is no longer just "can I rank on page one?" It's "can I become the source Google's AI cites?"
The businesses that will win search traffic in the AI Mode era are the ones whose websites give AI the clearest, most structured, most authoritative answers to service-category questions — not the ones with the most backlinks from 2019.
What that looks like in practice:
The study is published. Google isn't reversing course on AI Mode. Here are five concrete actions to take before next Friday:
1. Check your Search Console AI report. Google now shows AI Mode and AI Overview impressions. Log into Google Search Console → Search Results → Filter by "AI Mode" and "AI Overviews." See which queries are triggering AI answers and how your impressions have trended. If you don't have this data yet, set it up today.
2. Audit your highest-traffic informational pages. Pull your top 20 organic landing pages from Search Console. For any page where traffic has declined more than 20% year-over-year, check whether AI Overviews are now appearing for that query. If they are, rewrite the page to be the AI's preferred source — lead with a direct answer in the first 50 words, add FAQ schema, and cite specific numbers or credentials.
3. Strengthen your Google Business Profile. Add at least five new photos, update your service descriptions to include specific service types (not just "plumbing" — say "water heater replacement," "drain cleaning," "emergency pipe repair"), and respond to every review from the past 90 days. GBP data feeds directly into local AI answers.
4. Build one piece of original, citable content. Publish a page this week that contains something genuinely original: a local pricing guide with real ranges ("In [City], a standard dental cleaning costs between $X and $Y — here's why"), a before/after case study with photos, or a step-by-step process guide. This is the content AI cites; generic "what is HVAC" pages are not.
5. Diversify your lead sources before you need to. Don't wait until Google traffic drops 30% to start building your email list, your referral program, or your paid Local Services Ads presence. The study confirms the trend is real and accelerating. Use this week to set up one new non-Google lead channel — even a simple SMS opt-in for past customers is a start.
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What exactly is Google AI Mode, and how is it different from AI Overviews?
AI Overviews are the shorter AI-generated summaries that appear above organic results in standard Google Search. AI Mode is a fully AI-driven search experience — powered by Google's Gemini model — that replaces the traditional blue-link results page with a long-form, conversational AI answer. AI Mode generates far fewer external clicks than standard Search, and the UPenn/Northeastern study found it also reduces user satisfaction.
How much traffic should my service business expect to lose from AI Mode?
The study found an 18.8-percentage-point drop in click-through rates when users were placed in AI Mode versus standard Google Search. That said, AI Mode doesn't activate on every query — local transactional searches (e.g., "plumber near me") are partially insulated by map packs and Local Services Ads. Your actual traffic impact depends heavily on your query mix. Informational and comparison queries are hit hardest; urgent local queries less so.
Can appearing inside AI Overviews or AI Mode actually bring me more traffic?
Yes — paradoxically. Appearing as a cited source within an AI Overview or AI Mode answer can deliver higher click-through rates than appearing only in standard organic results, because the citation link is prominently placed inside the AI answer itself. The goal is to optimize your content to be the source AI cites, not just to rank in the standard results below the AI answer.
Should I be worried about competitors outbidding me on Local Services Ads as organic traffic declines?
Yes, and you should get ahead of it now. As organic clicks shrink, more service businesses are shifting budget to Local Services Ads (LSAs) and Google Ads, which tend to increase competition and cost-per-lead. The businesses that invest in LSA optimization — including Google Screened verification, review volume, and rapid lead response — before the rush will pay less per lead than those who scramble later.
Does this study mean SEO is dead for service businesses?
No. The study actually reinforces that SEO still matters — it's just that the goal has shifted. Being cited inside AI answers requires the same fundamentals as traditional SEO (authority, relevance, structured content) but rewards businesses that publish specific, original, well-structured answers more than those chasing generic keyword rankings. SEO isn't dead; it's bifurcating into "rank in AI answers" and "rank below AI answers," and the former is where your energy should go.
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