I stopped trusting share of voice about ten years ago.
Not because it doesn't measure anything. Because it measures the wrong thing — how loud you are, weighted by how loud competitors are, filtered through the coverage decisions of a shrinking press. It correlates weakly with what buyers do and strongly with what agencies want to bill for.
The metric I've come to trust more — the one I now watch weekly for every serious client — is Share of Search. It measures something real: the percentage of category-relevant search interest going to your brand versus your competitors.
Here is what it is, how to calculate it, and why it's the closest thing to a leading indicator I've found for brand momentum.
What Share of Search Is
Share of Search = Your Brand's Search Volume ÷ (Your Brand + Your Direct Competitors' Search Volume)
That's the whole formula. Take your brand's monthly search volume. Take the search volume of your named direct competitors. Divide yours by the total.
The number tells you what percentage of category-interested searchers are looking specifically for you.
A Worked Example
Imagine you run a mid-market cybersecurity vendor. Your named competitors are five other vendors in the same buyer conversation. Last month's branded search volume:
Your brand: 8,200 searches
Competitor A: 12,500 searches
Competitor B: 9,800 searches
Competitor C: 6,100 searches
Competitor D: 4,500 searches
Competitor E: 3,900 searches
Total category branded search: 45,000. Your Share of Search: 8,200 / 45,000 = 18.2 percent.
Track that number monthly. Watch what it does after major campaigns, product launches, coverage moments, category shifts. The trend line tells you whether the market is moving toward you or away from you — long before revenue reports do.
Why It's Better Than Share of Voice
It measures buyers, not press. Search volume is generated by people looking for information about your category. That's your audience, quantified. Share of voice measures press mentions — which correlate with buyer interest weakly at best.
It's harder to game. Your PR team can produce more press mentions through more pitching. Your PR team cannot produce more search volume through more pitching. Real demand shows up in real search data.
It's a leading indicator of category share. Multiple academic studies have shown that Share of Search correlates with future market share. Not every quarter, but reliably over time.
It's cheap to measure. Google Trends. Ahrefs. SEMrush. All accessible with existing tooling. No extra data purchases required.
It's harder to argue about. Search volume is what it is. Sentiment scoring has judgment calls. Coverage counts have quality caveats. Search volume is measured, dated, publicly available data.
What Share of Search Does Not Do
Doesn't tell you why searchers are searching. Positive interest or a crisis both produce search volume. Interpret with context.
Doesn't measure unaided awareness for people not searching yet. Some categories are dominated by early-stage buyers who search intensively; others by long-cycle buyers who don't. Category behavior matters.
Doesn't distinguish quality of interest. A million searches from unqualified buyers might be worse for the business than 100,000 from your target ICP.
Doesn't capture the AI-engine layer directly. More and more research now happens inside ChatGPT and its peers. Share of Search still matters — but it needs to be paired with Citation Share for a complete read.
How to Actually Use It
Establish a baseline. Twelve months of historical data before drawing conclusions.
Report it quarterly to leadership. Trend line, not just the current number.
Pair it with Citation Share. The two together give you traditional-search and AI-search visibility. Neither alone tells the whole story now.
Watch the correlations. When Share of Search moves, does it precede movement in inbound demo requests, deal cycles, or category coverage? Understanding your own correlations lets you use Share of Search as a leading indicator for the metrics your business actually cares about.
Don't obsess over month-to-month. Categorical noise is real. Direction over quarters matters more than any individual month's number.
The Metric That Now Sits Alongside It
Share of Search measures traditional search-driven demand. Citation Share measures AI-engine visibility — the percentage of relevant AI-engine queries where your brand appears in the answer. As more research shifts to AI engines, tracking both is now essential.
The best comms and brand teams I work with report both metrics quarterly, side by side. They tell you where your brand stands in the world buyers actually inhabit — half in traditional search, half in AI answers, and increasingly hybrid.
The Bottom Line
Share of Search is not perfect. It is the most trustworthy leading indicator of brand momentum I've found across two decades of client work. It's public, cheap, hard to game, and correlated with the future numbers that leadership actually cares about.
If you're measuring share of voice and calling it done, you are measuring how loud you are. If you're measuring Share of Search — and now Citation Share alongside it — you are measuring what the market is doing.
FAQ
What is Share of Search?
Share of Search is the percentage of category-related branded search volume that goes to a specific brand versus its named direct competitors. It is calculated as the brand's search volume divided by total category search volume across the named competitor set.
How is Share of Search different from Share of Voice?
Share of Voice measures a brand's share of press mentions in a category. Share of Search measures a brand's share of search interest. Share of Search correlates more directly with buyer demand and future market share.
Should Citation Share replace Share of Search?
No — they should sit alongside each other. Share of Search measures traditional search-driven demand. Citation Share measures AI-engine visibility. Both matter as buyer research increasingly happens across both channels.