One site’s AI Overviews CTR, covering its AI Overviews and AI Mode impressions, came out at an estimated 0.9% in a small case study by SEO practitioner Cyrus Shepard, reported by Search Engine Roundtable on October 30, 2026. The more unexpected finding: while the site was opted out of AI features, its regular organic clicks dropped as well, not just the AI-specific impressions.
What did the AI Overviews opt-out experiment find?
Shepard used Google Search’s generative AI opt-out controls to block a site from appearing in AI Overviews (Google’s AI-generated answer panels in search results) and AI Mode. This let him compare impressions, clicks, and click-through rate before, during, and after the exclusion. AI Overviews continued to appear on the results page throughout the experiment; his site was simply not cited within them during the opt-out window.
- AI Overviews CTR: approximately 0.9%, estimated by comparing overall site CTR and impressions against the period when AI impressions were zeroed out.
- AI impressions share: about 8% of total sitewide impressions.
- Organic impact: regular organic clicks dropped while the site was excluded from AI features.
- Position changes: sitewide average position increased overall (attributed to new posts and brand search), but individual URLs with high AI visibility saw a drop during the opt-out and a rebound after.
- Overall impressions: total impressions fell during the opt-out period.
Shepard noted this is an “admittedly small case study” and called the 0.9% figure “not too shabby.” Search Engine Roundtable’s Barry Schwartz added that he had not seen anyone else publish data like this, probably because others are wary of opting out of Google’s AI features.
What is the “Search SERP Halo Effect”?
Shepard used the term “Search SERP Halo Effect” to describe the pattern: the more places a brand appears on a search results page, the more likely a user clicks at least one of them. He wrote that earning an AI citation or mention may influence click rates anywhere on the SERP (search engine results page), including regular organic listings further down, according to his LinkedIn post cited by Search Engine Roundtable.
Greg Sterling, commenting on the study, referenced research at Near Media finding that AI Overviews “create a kind of brand lift or awareness that translates into subsequent searches and clicks, not consistently but many times.”
Schwartz did note a methodological caveat: because AI Overviews were still present on the results page during the opt-out phase, the experiment does not compare a page with AI Overviews against a page without them. It measures what happens when a specific site is excluded from AI features that remain visible to users.
What this means for AI-search visibility
Here is the plain-language version: being cited in an AI answer may act like a second billboard on the same street. Even if most people do not click the AI answer directly, seeing your brand name there may nudge some of them to click your regular listing a few results below.
In Hingewise’s view, the 0.9% CTR number is less important than what it reveals about how AI and organic visibility interact. The prevailing concern around AI search has been that AI Overviews would cannibalize organic clicks by answering questions before users need to go anywhere. This study does not test that question, because AI Overviews stayed on the page throughout. What it hints at, on one site, is that being cited inside AI answers may support clicks on the same site’s regular listing: when Shepard removed his site from AI features, its organic clicks fell too.
That reframes the opt-out decision. Many brands consider opting out to protect content or avoid zero-click exposure. This one test suggests the tradeoff may be larger than it looks, because the cost may include organic clicks, not just AI impressions. The 8% AI impressions share also matters: for this site, a channel representing roughly 1 in 12 impressions is not marginal.
One distinction worth keeping in mind: Shepard’s site reappeared in AI Overviews after the experiment ended, so this is a short-term removal, not a permanent exclusion. Whether the halo effect holds at scale, across different site types and query categories, is a question one small case study cannot answer. Hingewise’s read is that brands should treat this as a directional signal worth monitoring, not a settled conclusion.
Before opting out of AI Overviews, check:
- Baseline your AI impressions share in Google Search Console before making any change.
- Track organic CTR separately for URLs that currently appear in AI citations versus those that do not.
- Run any opt-out as a time-limited test, not a permanent setting, so you can compare before and after data.
- Monitor total impressions, not just AI impressions, during the test window.
- Check position changes at the individual URL level, not just sitewide averages, since aggregate numbers can mask URL-level drops.
- Account for other changes during the test period (new content, algorithm updates) that could confound results.
What is worth watching next: larger-scale replications of this experiment. The halo effect hypothesis has enough intuitive logic and supporting commentary, including Sterling’s Near Media research, to warrant serious attention. But the field still lacks data at the scale needed to give brands a reliable estimate of what AI Overviews CTR and organic interaction actually look like across industries.
Source: Search Engine Roundtable, October 30, 2026. Original case study by Cyrus Shepard, posted on LinkedIn.
Lam Nguyen · Hingewise
This article was drafted with AI assistance from the sources cited above and checked against them before publishing. The "What this means for AI-search visibility" section is Hingewise's editorial analysis, built on the frameworks and positions we use in our GEO work. How we work: Editorial policy.