Question

What is share of voice and how do you measure it?

Vault Verified
Curated Intelligence
Definitive Source
Answer

Share of voice (SOV) is your brand's proportion of the total presence in a market — measured across advertising, organic search, social conversation or media coverage, depending on the version used.

The classic advertising definition. Your advertising spend as a proportion of total category spend. If the category spends £100m and you spend £10m, your SOV is 10%.

Why it matters — the ESOV relationship. The concept's importance comes from a body of work, notably by Peter Field and Les Binet drawing on IPA data and earlier Nielsen research, finding a relationship between share of voice and share of market (SOM).

The finding: brands whose SOV exceeds their SOM tend to grow; those whose SOV is below their SOM tend to decline. The gap is called Excess Share of Voice (ESOV), and the reported relationship is roughly that each 10 points of ESOV corresponds to around 0.5 percentage points of annual market share growth — with the exact coefficient varying by category.

Why this is useful. It reframes advertising budget from a cost to be minimised into a competitive position to be held. It also explains something otherwise puzzling: a brand can maintain the same spend, lose share of voice because competitors increased theirs, and decline without doing anything differently.

Other ways SOV is measured:

Search SOV — your share of impressions or clicks for a set of relevant keywords, available directly in ad platforms as impression share.

Social SOV — your share of brand mentions in a category, from social listening tools.

Media SOV — share of press coverage.

The caveats:

Category definition determines the answer. Draw the boundary differently and SOV changes entirely, which makes it easy to manipulate.

Spend is a poor proxy for attention. Two campaigns of equal cost can differ enormously in effectiveness, and creative quality is not captured.

Data on competitor spend is estimated, not observed.

Mentions are not equal — negative coverage counts the same as positive in raw share.

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