Attribution Models

An attribution model is the rule Google uses to decide which ad interactions get credit for a conversion.

You run into this the moment a customer touches more than one ad before buying. Someone clicks a search ad on Monday, sees a Shopping ad on Wednesday, comes back through another search ad on Friday, and finally purchases. Which click gets the sale? The attribution model is the rule that answers that question, and it quietly shapes every performance number you look at.

The choices are much simpler now than they used to be. Google made data-driven attribution the default for most conversion actions, and it retired the old rule-based models, first-click, linear, time-decay, and position-based are all gone. That leaves you two options: data-driven, which uses your account's own conversion patterns to spread credit across the touches that actually mattered, and last-click, which hands all the credit to the final click. Conversion actions that used a retired model were automatically upgraded to data-driven.

Where this bites you. Data-driven is a model you cannot fully see inside, and it splits credit across multiple touches, so your Google numbers will not line up with a naive last-click view or with another platform that credits itself for the same sale. If Meta and Google both claim a conversion, they are often both looking at the same customer through different rules. Before you compare anything, know which model you are reading.

The number only means something once you know the rule behind it.