HawkscanShare of search
Share of search is a brand metric that measures the searches for one brand as a percentage of the searches for all brands in its category, usually with Google Trends data. Les Binet presented it at the IPA's EffWorks Global 2020 conference as a fast, cheap predictor of market share.
Why share of search matters
Share of search matters because it moves before sales do. Les Binet, of the agency adam&eveDDB, tested it in three categories, cars, energy and mobile phone handsets, and found that it correlated with market share in all three. It also worked as a leading indicator, with a lead time of "up to a year for cars." The data is free: Google Trends generally goes back to 2004 and can be read weekly. Binet stated the limits too. Conversion depends on other factors, "particularly price", and "not all search activity is positive."
How share of search works
- List the brands in the category, yours and your competitors.
- Pull their search interest from Google Trends, in one comparison, over the same period and region.
- Add up the searches for all the brands.
- Divide each brand's searches by the total.
Binet counts organic searches for brand names, not paid search advertising. The metric suits categories where people look brands up by name. It says little about how people discover a brand they have never heard of, which is where AI answers come in.
Formula
Share of search = searches for the brand ÷ searches for all brands in the category × 100
Worked example (fictional values). Four meal-kit brands get 40, 30, 20 and 10 points of search interest in Google Trends over the same month. The first brand's share of search is 40 ÷ (40 + 30 + 20 + 10) = 40%. If it slips to 35% while its market share holds, Binet's work suggests market share may follow.
Share of search vs AI visibility
Share of search and AI visibility capture two different moments: what people type once they know a brand, and which brands AI assistants name when people ask for advice. The two are linked. In an Ahrefs study of 75,000 brands, branded search volume correlated with AI mentions at 0.352 in ChatGPT, 0.392 in AI Overviews and 0.466 in AI Mode. The AI metric built the same way is AI share of voice: a brand's mentions as a share of all tracked brands' mentions in AI answers.
| Share of search | AI visibility | |
|---|---|---|
| Source | Brand searches on Google | Answers from AI assistants |
| What it reflects | Demand for brands people already know | Recommendations to buyers who ask for advice |
| Main tool | Google Trends | Prompt tracking across engines |
How to track share of search with your competitors
Measure share of search monthly against a fixed set of competitors, then put it next to how the same brands fare in AI answers. A brand whose searches grow while it stays absent from AI recommendations has a discovery problem worth fixing. Hawkscan ranks every tracked brand, yours included, by AI visibility score, mention rate or average position in the answers of ChatGPT, Microsoft Copilot, Gemini and Google AI Mode.
