Google began adding AI Overviews (AIO) to the U.S. search results on May 14. While vaguely mentioning that links in AIO get higher click-through rates (CTRs), Google has remained evasive when directly asked about this.
When discussing this important topic with my clients, we talk about two things:
Also, although I mostly focus on AI Overviews here, much of the same thinking and concerns apply to Bing Copilot.
Google AI Overviews and Bing Copilot offer a new way to interact with search results. This new user experience starts when the user engages with the generative AI (e.g., generating an AIO response, expanding a pre-generated one, submitting a prompt).
The generative AI user interfaces from Google and Bing take over the search results, presenting a much richer response to the user’s query compared to traditional search engine result pages.
Searchers are more satisfied when AIO are shown, according to Liz Reid, Google’s VP and head of Search. AIO typically provides a summary of the main query topics with brief explanations for each subtopic, including links to non-Google websites.
Regarding CTR, if the AIO summary is divided into multiple sections, each section typically contains one or more links. Additionally, Bing’s Copilot functions as a single-page app, providing a more interactive and iterative search experience compared to traditional Bing results.
Thinking around CTR requires needs to evolve, with more nuance, because traditional search result pages differ from the generative AI user interfaces.
This is why Google and Bing’s evasiveness on this topic is frustrating.
When considering this, I focus on two potential extreme scenarios for the searcher:
A key observation: The generative AI user interface is very dominant with fewer clickable targets compared to other search features.
Notably, the links in AIO are more prominent and richer than typical search results, featuring site names, headings, snippets, and potentially images – all packaged in a card-like format beckoning clicks.
So when searchers want to click a link, the mere fact that there are fewer prominent click targets in AIO (compared to the 10 blue links) can only lead to a higher CTR.
Mathematically, the denominator is the number of click targets, and the smaller the denominator, the higher the CTR.
The key question to carefully consider: how often do searchers want to click a link? Only Google can definitively answer this because that data is not public. We’ll discuss how to get a proxy measure of this later in this article.
The most direct statement is from Reid’s announcement:
Annoying, right? This sentence is vague, lacks context and appears to be an attempt by the corporate communications team to obfuscate bad news.
Let’s examine some possible interpretations:
Google calculates CTR as clicks per search feature. For example, AIO, sitelinks, Knowledge Panels, and featured snippets each have their own CTR.
The UX argument is that a more dominant interface gets more clicks. Because AIO is very dominant (Copilot takes over the whole screen), it will have a higher CTR for its links.
Within any search feature, different links get different CTRs. For example, in the 10 blue links, Position 1 has a higher CTR than Position 9.
AI Overviews usually shows between two and five links, much fewer than the 10 blue links typically displayed.
Because AIO offers fewer links, the CTR for each link within AIO is higher compared to links in the 10 blue links.
We can compare the same link in AIO versus other search features. Due to AIO’s prominent display, engaging context and fewer links, the CTR for a link in AIO is likely higher than in other search features.
Several factors complicate understanding AIO’s performance:
One thing Google and industry commentators haven’t discussed is the overall CTR from the search results page to the wider web.
The presence of any search feature can impact the CTR of links within that feature and other search features.
Given this, it’s likely that the prominent AIO and Copilot on the SERP reduce clicks on other features, especially the 10 blue links.
This means the CTR of links in AIO might be higher, but overall, the SERP might generate fewer clicks.
The result could be more search sessions with zero clicks.
If true, this has huge implications for organic search traffic to all websites.
So which CTR interpretation is Google referring to?
I believe it’s the third one: a link is more likely to have a higher CTR if shown in AIO compared to one of the 10 blue links.
The problem is that we don’t know how Google and Bing measure CTR for these new user interfaces and they’re avoiding the question.
We need more transparency from the search engines.
Instead of avoiding these questions, the search engines should clearly explain how they measure CTR and other metrics for the new UX.
While we wait for Google to share better data, what can we do to measure the impact of AI Overviews?
To gauge the impact, I’ve been using three data sources with my clients to sketch a rough picture:
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. This format highlights specific parts of the page in SERPs for featured snippets and AIO links. You should be tracking this already!Reporting on these three data sources in a business-friendly format helps you estimate how often:
While imperfect, it provides a directionally correct view.