AI Search: Which KPIs to Measure

4.4x — that's how much better visits from AI search convert compared with standard organic traffic. At the same time, organic CTR drops by as much as 61% when an AI answer sits above the results, and Google now shows AI Overviews on roughly 48% of searches. The conclusion is simple: counting traffic and rankings alone no longer works — those are the very "vanity metrics" experts have long warned about.

HubSpot proposes a set of KPIs that show the real business contribution of AI search. The logic runs from visibility to money: first log where you're mentioned, then whether it leads to revenue. The full breakdown is published by HubSpot.

What belongs in your report:

• Mention and citation share — the share of prompts where your brand appears, and how it stacks up against rivals;
• Accuracy and sentiment — whether the AI describes your product correctly and in a positive light;
• Branded demand lift — month-over-month growth in branded queries;
• AI engagement and conversion — time on site (notably higher for AI visits), depth, and sales from this source specifically;
• Revenue contribution — via CRM and a "how did you hear about us" question.

Start with two or three metrics you can already see: mention share, branded demand and AI-traffic conversion. Bare visibility without citation context is a vanity metric again; the value shows up where the number sits next to the money.