Learn & Understand

The SOV/SOM Research That Turned a Metric Into a Growth Theory

Share of Voice is a simple ratio - a brand's ad spend divided by total category ad spend - but it became a foundational concept in advertising budget planning because of a body of research connecting it to something advertisers actually care about: future market share growth.

The Original Observation: SOV Consistently Running Ahead of SOM

Advertising effectiveness researchers, including influential work often associated with John Philip Jones in the 1990s and later expanded by the Ehrenberg-Bass Institute for Marketing Science, observed a recurring pattern across many product categories and brands: brands whose Share of Voice consistently exceeded their existing Share of Market tended to grow their actual market share over subsequent periods, while brands under-investing in advertising relative to their market position tended to see share erosion instead. This relationship became known informally as the "SOV/SOM gap," with a positive gap (spending proportionally more on advertising than your current market share would suggest) treated as a leading indicator of future growth.

Why This Relationship Makes Intuitive Sense

The underlying logic connects to broader findings in marketing effectiveness research about how advertising works cumulatively over time to build and reinforce mental availability - the ease with which a brand comes to mind in a buying situation - rather than driving purely short-term transactional responses. A brand maintaining an advertising presence disproportionate to its current size is, in effect, continuously investing in exactly this kind of long-term brand salience ahead of where its current sales would otherwise justify, which the research suggests pays off in gradually increasing market share as that elevated presence compounds over multiple years.

Why Measuring "Total Category Ad Spend" Is Genuinely Difficult

Despite SOV's conceptual importance, actually calculating it in practice runs into a real measurement challenge this calculator's simple formula doesn't fully surface: reliably estimating total advertising spend across an entire competitive category, including competitors who don't publicly disclose their marketing budgets, requires third-party media monitoring services, industry estimates, or reasonable approximation - it's rarely a precisely knowable figure the way a single company's own ad spend is. Most real-world SOV calculations, as a result, rely on estimated or monitored competitive spend data with some inherent uncertainty, rather than exact, audited figures for every competitor in a category.

Applying This When Setting an Advertising Budget

Rather than treating SOV purely as a competitive benchmarking curiosity, comparing it explicitly against current market share - and treating a persistent SOV/SOM gap in either direction as a signal worth acting on, in the growth-planning tradition this research established - turns a simple spend ratio into a genuine strategic input for advertising budget decisions, provided the underlying total-category spend estimate is reasonably reliable to begin with.