A comprehensive analysis of UK media effectiveness reveals that audio advertising sizeably outperforms other channels in return on investment, reinforcing similar findings from recent US radio effectiveness studies that show AM/FM delivering returns as high as 18:1.
The High Gain Audio report, conducted by WPP Media EVP Analytics Jane Christian and Radiocentre Planning Director Mark Barber, examined £148 million in media spend across 141 brands between 2021 and 2023. The findings show audio generating 32% higher short-term profit ROI and 21% higher full-term ROI compared to the all-media average.
These findings align with recent US radio effectiveness research.
Analyst Peter Field, drawing on a decade of campaign data, found that brands using radio gained stronger market share, pricing power, brand recall, and return on investment than those that did not. Nielsen’s analysis reached a similar conclusion, reporting that radio delivers $10.59 in return for every dollar invested.
The UK study further separated broadcast radio and digital audio to compare their individual performance across seven brands. Digital audio produced £5.20 in long-term returns per pound spent, with broadcast radio close behind at £5.00. In the short term, digital audio delivered £2.70 per pound and broadcast £2.30 — both ahead of paid social at £1.50 and online display at £1.20.
Both formats significantly outperformed the all-media average of £1.90 short-term and £4.10 long-term.
The superior performance of audio advertising in the UK mirrors US market trends. 2024 research by Katz Radio Group found that across key holiday verticals, radio delivers an average return on ad spend of $18 for every $1 invested, with categories such as grocery stores, department stores, and mass merchandisers benefiting notably from radio’s effectiveness.
The WPP analysis also shows the power of integrated audio.
Campaigns that devoted a portion of budget to multiplatform audio saw overall ROI rise 5% in the short term. When audio was maximized to 24% of total spend, ROI climbed by 8.2% compared to campaigns without audio. U.S. research mirrors this, with Field’s work demonstrating that AM/FM raises mental availability by 13%, lifting market share by 28% among brands using broadcast.
Importantly, the study identified room for further growth. Broadcast radio could sustain 90% more investment while digital audio could expand by 130%, based on marginal ROI thresholds. That potential is reinforced by radio’s unmatched reach.
In the US, AM/FM engages 84% of adults weekly, outpacing connected TV, smartphones, streaming services, and podcasts.
Researchers recommend three strategies for maximizing results. First, increase audio allocations to around 20% of total media spend, far higher than current norms. Second, use digital audio to complement, not replace, broadcast radio, ensuring maximum weekly reach. Finally, update marketing mix models to separately measure broadcast and digital audio, enabling more accurate optimization.
