Blis research highlights concerns over data accuracy

The research highlights growing uncertainty around audience targeting as the advertising industry adapts to a digital environment increasingly shaped by cookie deprecation and signal loss.

Blis, part of T-Mobile Advertising Solutions, has found that 95 percent of UK marketing decision-makers are concerned about the long-term viability of their current data strategies.

Conducted by Sapio Research among 200 senior UK marketing decision-makers in June 2026, the study found that more than 70 percent of web traffic is now cookie-free. It also revealed widespread scepticism about alternative targeting solutions, with 82 percent of respondents stating that lookalike or expanded audiences are only as effective as the underlying seed data.

Data accuracy remains a major targeting challenge

The findings point to data integrity as a central concern for marketers. Some 78 percent of respondents said the quality of initial source data directly affects campaign performance, while 59 percent identified data accuracy as their biggest audience targeting obstacle.

Other challenges included cross-platform consistency, cited by 45 percent, and signal loss or user privacy concerns, mentioned by 39 percent. In addition, 69 percent said single-channel and siloed data sources provide a fragmented view of the customer journey. Fewer than half (48 percent) expressed confidence in the accuracy of their existing audience inputs.

Telco data emerges as an alternative audience signal

Despite these concerns, marketers see potential in telecommunications data as an alternative source for omnichannel targeting. Some 82 percent of respondents believe telco data could become an essential signal for future targeting strategies, while 59 percent identified accuracy and quality as its main advantages.

To assess its effectiveness, Blis conducted campaign tests across five UK consumer categories: travel and tourism, health and fitness, food and restaurants, music and movies, and clothing and fashion. The experiment compared standard campaign targeting with an approach that incorporated telco-verified data signals.

The results showed statistically significant increases in category affinity across all five segments, ranging from 38 to 155 percent.

Blis highlights the role of telco signals in targeting

Telco data uses signals such as app usage and movement patterns collected through mobile networks. According to Blis, these signals can support audience targeting without relying on cookies or device IDs, addressing several of the data challenges identified in the research.

Charlie Smith, CRO at Blis: "Data accuracy is not optional in the evolving digital landscape. This research makes it clear: signal loss is a significant and urgent issue for many of the UK’s most influential marketers. The vast majority are very aware that traditional data sources just aren’t fit for modern marketing purposes.

“As modeling and automation play ever greater roles within digital, they can only ever be as good as their foundational seed data. The opportunity presented by trusted telco data, especially provided through an omnichannel DSP like us, is simultaneously reliable, privacy-first, and highly actionable. This study demonstrates it can deliver exceptional precision and, crucially, outcomes."

www.blis.com

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