Research from Prohaska Consulting, commissioned by Rakuten Rewards has found that MMM is penalising affiliate marketing.
Marketing mix modelling (MMM), has measurement flaws causing it to misread the performance of affiliate marketing campaigns, new research has revealed.
The study, titled The Next Frontier of Measurement: Fair Evaluation of Affiliates in Marketing Mix Models, from Prohaska Consulting, commissioned by Rakuten Rewards, analysed specialised data and performance metrics from senior marketing leaders across agencies, retailers, and Rakuten Rewards.
According to the report, over 80% of marketers utilise affiliates, and Rakuten data showed that the strategy offers up to 17 times return in sales in comparison to commissions via cash back initiatives. In fact, 65% of retailers reported that affiliate programmes increase annual revenue by up to 20%.
Although affiliate marketing is a growing industry with global revenue valued at $18.5bn in early 2026 (projected to reach $31.7bn by 2031), the industry is not a monolith – and treating its diverse channels like influencers, cash back and coupons, as such is damaging reporting.
Some affiliate programmes, such as cash back, focus on conversion and performance, which means it has a much lower data quality in MMM compared to Google or Facebook.
The report identified that although marketers are aware of the meaningful value and incrementality that affiliates bring, MMM makes this difficult to quantify, and the data needed to calculate ROAS and iROAS are often not fully captured within existing models.
Affiliate is often used as a catch-call category, and is not clearly defined as a channel including a diverse range of influencers, review sites, cash back, and loyalty programmes.
As the definition is not standardised for clicks and impressions across partners, this can lead to a delay in reporting, and an inconsistency in results. Respondents to the survey also reported that affiliates are often treated as ‘placeholders’ within MMM structures.
“Most marketers don’t realise how much affiliate performance is being underrepresented in their models, and that gap has real dollar impact,” said Ameet Shah, partner at Prohaska Consulting.
“The capability to more accurately measure exists, but it’s not being applied effectively. With consistent data inputs and alignment across the ecosystem, it can be.”
The report suggests direct integration from affiliate to MMM, with automated data feeds, standardised data formats, and impression and engagement metrics to help establish clearer boundaries for tracking performance.
Carl Lurie Kalapesi, chief commercial officer at Rakuten Rewards, added: “We’ve sat across the table from brands that pulled back on affiliates because their MMM told them to do so, and they spent the next year trying to win back ground they didn’t need to lose.
“Affiliates deliver consistently and at scale, and this research gives marketers evidence and the framework to prove it. Getting the measurement right is more than just a technical fix. It is often the difference between growing market share or handing it to a competitor.”
