Attribution Model

An attribution model decides which touchpoint gets credit for a conversion when a customer interacted with more than one channel. Imagine someone sees a Facebook ad, comes back later through a Google search, and buys. Last click gives all the credit to the Google search. Data-driven attribution splits the credit based on how each touchpoint actually changed the chance of converting across your account’s data.

GA4 now offers only a few models. Data-driven is the default. Paid and organic last click gives full credit to the final non-direct click. Google paid channels last click gives credit to the last Google Ads click if there was one. In 2023 Google removed first click, linear, time decay, and position-based models from both GA4 and Google Ads, so older guides that compare all of them describe options you can no longer choose.

The lookback window sets how far back GA4 looks for touchpoints. Acquisition key events (first_visit and first_open) default to 30 days and can be set to 7 or 30. All other key events, like purchase or generate_lead, default to 90 days and can be set to 30, 60, or 90. Changes apply across the whole property and only affect data from that point forward, not past reports.

Use the model comparison and conversion paths reports to see how credit shifts between channels. Those reports won’t tell you which model is true, but they show which channels are being under or over credited by last click.