Until being voted the best medium for building brand fame at this year’s Media 360, commercial radio has typically been typecast as short-term tactical medium. So what changed? In support of a broader marketing campaign designed to encourage more ambitious brand-led use of radio, this study set out to challenge the notion that brand-building can only be achieved with audio-visual media. It used the frameworks described in Byron Sharp’s popular How Brands Grow theory to provide new measures showing how radio drives brand growth alongside TV and, equally importantly, to attract the interest of the agency planning community. With its best practice creative & media guidelines Radio: the Brand Multiplier is helping advertisers to apply the findings and enhance their results by leveraging the historically underused brand effects of radio.