Half of Marketers Still Can't Prove Influencer Marketing Works

Aug. 27, 2025

New research from social-first agency SAMY has revealed that half of marketers (50%) are still unable to prove a return on investment from influencer marketing, while nearly as many (48%) admit they don’t know how to drive sales through influencer content.

This is in spite of influencer marketing investment continuing to grow. According to Kantar, 53% of marketers globally plan to increase their influencer spend this year, while global giant Unilever has committed to working with 20 times more influencers in 2025.

SAMY’s survey was carried out among senior marketers at 70 global consumer brands, exploring the challenges marketers encounter when working with influencers

Finding the right influencers remains the biggest hurdle. Sixty percent say they struggle to identify influencers who truly fit their brand and connect with their audience.

Just under half (44%) say they’re running campaigns without clear KPIs in place, making it harder to measure success or scale what works.

For 40% of brands, the challenge lies in building long-term loyalty. Many still rely on one-off posts instead of deeper, ongoing collaborations with influencers that drive sustained engagement. Moreover, 30% of marketers say they’re unsure how to gauge the power of influencers to grow a brand’s community.

SAMY’s research suggests that many brands are repeating an age-old industry pattern: investing substantially before fully understanding effectiveness. UK TV adspend alone is forecast to reach £3.8bn in 2025, yet 63% of marketers say they still struggle to measure TV’s effectiveness accurately.

To support brands in professionalising their influencer marketing strategies, SAMY has developed its "Influencer Marketing Maturity Model", a framework for brands to evaluate their capabilities and progress against four key pillars: influencer selection, strategic integration, creativity, and performance measurement. 

By identifying their maturity level in those four areas, brands will be able to identify exactly where they need to improve and build a structured, scalable approach to influencer marketing.

Juliet Howes, Influencer Marketing Director at SAMY said: 

“Influencer marketing has evolved into a core component of modern brand strategy, as evidenced by growing investment from brands into a wider range of influencers. But as our research shows, many brands are still operating with fragmented approaches: a short-term outlook, limited measurement, and little integration across teams or channels. While tools like audience analysis, social listening and campaign tracking are becoming more widely adopted, our findings suggest that to see true value from influencer marketing, brands still need to integrate influencers more deeply, adopt a clearer strategy, and improve internal coordination. Brands that are treating influencers as long-term partners and strategic collaborators, supported by the right tech, a clear framework, and KPIs that go deeper than vanity metrics are the ones most likely to solve the ROI conundrum.”