Share of Voice (SOV)
The percentage of category ad presence a brand owns versus competitors.
Share of Voice (SOV) is a competitive intelligence concept that ecommerce teams touch every week, usually without agreeing on a definition first. This page sets out what it means, how to apply it at catalog scale, what to measure, and where it breaks.
Definition
Share of voice measures a brand's presence in a category — impressions, spend, mentions — against total category activity.
Why it matters
SOV above natural market share correlates with future market share gains — the Byron Sharp / Ehrenberg-Bass insight.
Formula
SOV = Brand Ad Presence ÷ Total Category Presence × 100
How to calculate and use it
The calculation itself is simple — SOV = Brand Ad Presence ÷ Total Category Presence × 100 — and the judgement is entirely in the inputs and the window you choose. Sample systematically: the same set of competitors, on the same cadence, across the same placements. Record the offer, the hook, the format and how long the asset has been in market. Turn the pattern into a hypothesis you can test in your own account, not into a lookalike file. Worked through: Your brand runs 12,000 ad impressions in a market where the top 5 competitors run 100,000 total = 12% SOV.
What to measure and watch
Track longevity and repetition rather than volume. An asset live for eight weeks is a stronger signal than fifty assets launched last Tuesday. Watch relative presence over time so you can tell a genuine push apart from routine rotation. Why this matters commercially: SOV above natural market share correlates with future market share gains — the Byron Sharp / Ehrenberg-Bass insight.
Failure modes worth naming
The recurring problems are predictable: measuring sov only in owned channels; ignoring share of search as a real-world sov proxy; comparing sov without adjusting for market share. Each of these is a process gap rather than a knowledge gap — which is why the fix is usually a checklist, a template or an automated rule instead of more training.
Your brand runs 12,000 ad impressions in a market where the top 5 competitors run 100,000 total = 12% SOV.
Common mistakes
- ✕Measuring SOV only in owned channels.
- ✕Ignoring share of search as a real-world SOV proxy.
- ✕Comparing SOV without adjusting for market share.