Last-Click Attribution

The standard affiliate commission allocation model in which 100% of the commission for a conversion is assigned to the affiliate publisher whose tracking link was clicked most recently before the purchase was completed, regardless of how many other affiliate publishers the customer may have interacted with during their purchase journey. Last-click attribution is the dominant model in affiliate marketing because it is simple to implement with standard cookie-based affiliate tracking, produces unambiguous commission assignments, and requires no cross-channel data integration. How last-click attribution works: when a user clicks an affiliate link, a tracking cookie is set in their browser containing the publisher's affiliate ID and the click timestamp; when the user completes a purchase within the cookie window, the tracking system reads the most recent affiliate cookie (in programs where multiple publishers may have set cookies) and assigns the conversion to that publisher. Last-click bias: last-click attribution systematically over-rewards publishers who capture purchase intent (coupon aggregators, loyalty programs, deal sites) relative to publishers who generate purchase intent (review blogs, comparison sites, YouTube reviewers); a customer who discovers a product through a review article and then clicks a coupon code immediately before purchase generates 100% commission for the coupon publisher and nothing for the review publisher; this attribution structure creates financial incentives that systematically favor certain publisher types over others. Alternatives: first-click attribution rewards discovery publishers; linear attribution splits credit across all touchpoints; position-based attribution weights first and last touchpoints more heavily; time-decay attribution rewards more recent touchpoints more heavily; data-driven attribution uses machine learning to estimate marginal contribution.