Study shows last-click attribution credits affiliates with nearly double their actual sales contribution

The BVDW, analyzing data from 185 German advertisers in 2025, found that last-click attribution overstates affiliate channel contribution by nearly double — attributing 24.92% of sales to affiliates when their actual involvement accounts for 12.41%. The research underscores a persistent gap between how the affiliate channel is measured and its genuine impact, even as affiliate spend in Germany reached €932m last year. The finding raises questions about why the industry continues to rely predominantly on last-click models despite their known limitations in capturing true channel value.