Share of search (SoS)
Cheapest, most predictive proxy for brand demand and future market share.
- Formula
- Brand's organic search volume / total category (all-competitor) search volume; via Google Trends / Keyword Planner
- Unit
- %
- Models
- All models
| All | SoS predicts market share ~6–12 months ahead (Binet / IPA 2020). Hankins/Vizer (IPA 2021): SoS explains ~83% of market-share variance across 30 cases and 12 categories. Use trend direction and Excess SoS (ESOS), not the absolute number. | Les Binet / IPA 2020; James Hankins / Vizer / IPA 2021 |
What it is
Share of Search (SoS) is the brand's organic search volume divided by the total search volume for the entire competitive category, typically estimated via Google Trends or Google Keyword Planner. It is a proxy for brand salience — how often people look for you relative to everyone in your space.
How to calculate it
Sum the brand's monthly organic search query volume, then divide by the combined volume of all tracked competitors plus the brand itself. The output is a percentage that shifts as the category grows, shrinks, or new entrants appear. Google Trends index values can be used when absolute volumes are unavailable.
Why it matters
Les Binet's IPA EffWorks 2020 research found that SoS is a leading indicator of market share, running approximately 6–12 months ahead. James Hankins and Vizer (IPA 2021) extended this, showing SoS explains roughly 83% of market-share variance across 30 cases and 12 categories. That predictive quality makes it a more actionable early signal than lagging revenue metrics.
Benchmarks & pitfalls
Because this is a directional measure rather than a rigorous cross-industry standard, there is no universal "good" absolute percentage — what matters is whether your SoS is above or below your market share (Excess SoS, or ESOS) and whether the trend is improving. The underlying dataset is over a decade old, the metric is volatile for small brands with low absolute search volumes, and competitor bankruptcies or viral moments can cause confounding spikes. Always interpret the trend and ESOS rather than fixating on the raw share number.