A new BVDW white paper makes a blunt case: if you judge affiliate and partner marketing only by the click that happens right before purchase, you are probably seeing half the picture. The paper, published October 22, 2026, argues that last-click attribution systematically undercounts the channel’s actual footprint.
The headline numbers
The study combined tracking data from 185 advertisers via three providers: attriXus, easy Marketing and Ingenious Technologies. Under last-click logic, affiliate touchpoints appear in 12.41% of transactions. Count any transaction with at least one affiliate touchpoint anywhere in the journey, and the share rises to 24.92%.
That is a factor of 2.01. As author Anna Babajeva puts it, “Actual contribution and visible contribution are a factor of two apart.” One caveat matters here: the higher number measures participation, not proven causation, and the paper itself notes that 39% of advertisers don’t measure incrementality at all.
Why the gap hits growth teams
Last-click credit flows to bottom-funnel partners such as cashback and voucher publishers. But the researchers say the fastest-growing segments sit further up the funnel: influencer and social content investment grew 21.4% in 2025, CSS grew 22.1%, and price comparison continues to gain share in Germany.
That creates a budget distortion. You underinvest in the partners that start demand, then conclude the channel underperforms. The paper’s broader market context is strong: €932 million was invested in German affiliate marketing in 2025, generating €18.7 billion in revenue and a 13:1 ROAS across the whole market, or 16:1 in retail and travel.
The numbers also come with a conflict of interest worth naming. The paper was written by executives from affiliate networks, platforms and agencies, and it leans on survey data from companies that employ its authors. That does not invalidate the finding, but it does make independent incrementality testing essential before you reallocate budget.
What to change
The authors recommend keeping last click for payouts, but using a hybrid or multi-touch model for strategic steering. Their “growth architecture” test has four parts:
- Full-funnel capable – partners active from awareness through loyalty
- Cross-channel compatible – affiliate data integrated with search, social, display, retail media and CRM
- Data and steering capable – CLV, purchase frequency and incrementality become main KPIs
- Modular and scalable – run as an actively managed portfolio, not a set-and-forget programme
For performance marketers, the practical move is to split the measurement layer from the payout layer. Last click is fine for commissions. It is a poor tool for understanding contribution, especially as AI shopping surfaces and server-to-server tracking reset where and how touchpoints happen.
Source: PPC Land
