Attribution Models
Attribution models distribute the credit for a conversion across the different marketing touchpoints a person passed through on their customer journey. Since November 2023 Google has retired the classic rule-based models — first click, linear, time decay and position-based — in GA4; what remains is mainly data-driven attribution together with last-click variants for paid and organic channels.
In practice
In practice GA4 uses data-driven attribution by default: machine learning works out the actual contribution of each click from converting and non-converting paths inside your own account. It is still worth looking at last-click figures when comparing channels, because many advertising platforms outside Google continue to credit conversions by their own logic. If you split budget between Google Ads, social ads and SEO, never judge a channel on a single model in isolation — always compare models side by side.