What is Last-Click Attribution?

Last-click attribution is the default attribution model for most mobile UA platforms: whichever ad received the final click before a conversion (install, purchase, registration) receives full credit. All previous ad interactions in the customer journey, earlier clicks, impressions, different channels, receive zero credit.

Last-click is simple, deterministic, and universally supported, which explains its dominance. Its weakness is systematic bias: it undervalues upper-funnel channels (awareness video, display) that contribute to the decision to convert but rarely receive the final click. It also overvalues retargeting and search ads that intercept users who were already intending to convert.

For mobile app UA where conversion journeys are typically short (same session or within 24 hours), last-click is reasonably accurate. For longer-consideration products with multi-touch journeys, multi-touch attribution models (linear, time-decay, data-driven) provide more accurate credit distribution.