Attribution assigns credit for a conversion to ads, clicks and other touchpoints using a rule or a model.
One order can receive different credit allocations
A shopper clicks a social ad, later searches for the brand and buys. Last-click and data-driven models may distribute credit differently. Align event definitions, lookback windows, models and data scope before comparing reports. Adding platform-reported conversions can double-count the same order.
Last click is not always the last visit
GA4’s paid and organic last-click model generally credits the last non-direct channel. Direct receives credit when the entire path is direct. An ad followed by a direct visit and purchase therefore need not be attributed to direct. Session acquisition and key-event attribution are different reporting scopes.
An AI comparison may be missing from the path
A person may learn about a brand in an AI conversation, never click, and later arrive through search. Website analytics may not observe the earlier interaction. Attribution depends on available data and modeling; estimating whether the ad generated additional purchases calls for incrementality measurement.
Sources
Definitions and source documents checked on 2026-11-07. Examples marked as illustrative are not measured results.