AI Overviews (AIO) are a new feature added to Google search results that provide a fundamentally different user experience. When a user engages with the generative AI, such as generating an AIO response or expanding a pre-generated one, the AI interface takes over the search results. This results in a richer response to the user's query compared to traditional search engine result pages. AIO typically provides a summary of the main query topics with brief explanations for each subtopic, including links to non-Google websites. According to Liz Reid, Google's VP and head of Search, searchers are more satisfied when AIO are shown.

The click-through rate (CTR) for AI Overviews (AIO) differs significantly from traditional search results. AIO typically shows fewer links compared to the 10 blue links in traditional search results, which can lead to a higher CTR for each link within AIO. The generative AI user interface is very dominant with fewer clickable targets, making the links in AIO more prominent and richer, often featuring site names, headings, snippets, and potentially images. This card-like format beckons clicks. However, the overall CTR from the search results page to the wider web might be reduced, leading to more search sessions with zero clicks.

Several factors complicate understanding the performance of AI Overviews (AIO):

1. Duplicate URLs: In traditional search, a URL appears only once in the top 10 results. During AIO’s testing phase, a URL could appear multiple times in the generative AI response.
2. CTR Measurement: AIO and Copilot are interactive, so the CTR varies greatly depending on whether it’s measured per search session or per query. Measuring per session is likely to show a higher CTR.
3. Variable Responses: AIO responses to the same query can vary significantly over time, including which links are shown and how the content is formatted (sections, image carousels, etc.).
4. Overall SERP CTR: The presence of AIO and Copilot on the SERP can reduce clicks on other features, especially the 10 blue links, potentially leading to fewer overall clicks from the SERP.

To measure the impact of AI Overviews (AIO) on website traffic, website owners can use the following three data sources:

1. SERP Tracking Tool: Use a tool like Authoritas to track how AIO appears in SERPs over time. The same query can get very different AIO responses, so any tracking tool must report these variations.
2. Web Analytics: Use Google Analytics or a similar tool to report on pages referred from Google containing #:~:text=. This format highlights specific parts of the page in SERPs for featured snippets and AIO links.
3. Search Console Data: Use the Search Console bulk export into BigQuery for richer data on page-query combinations. Analyzing this data for AI Overviews and featured snippets is crucial.

Reporting on these three data sources in a business-friendly format helps estimate how often AIO appears for a query, how often your website is shown in AIO, and how often your site gets clicks from AIO.

Google's vagueness about the impact of AI Overviews (AIO) on click-through rates (CTR) might be due to several reasons:

1. Communication Issues: Google may be telling the truth but poorly communicating this interesting fact.
2. Intentional Evasiveness: Google might be vague on purpose to avoid revealing potentially negative implications for traditional search results and organic search traffic.
3. Complexity of Measurement: The new generative AI user interfaces from Google and Bing are fundamentally different from traditional search result pages, making it challenging to measure CTR in the traditional way.
4. Dominant Interface: The generative AI user interface is very dominant with fewer clickable targets, which can lead to a higher CTR for links within AIO but might reduce the overall CTR from the search results page to the wider web.

The lack of transparency from search engines like Google and Bing on how they measure CTR for these new user interfaces is frustrating and calls for more clarity.