Attribution model
An attribution model is the rule that decides how to split the credit for one order among the ad clicks and channels a customer went through before buying.
How it works
When a customer clicks several ads before ordering, the model decides which click gets the credit. Last click gives all of it to the final click. Data-driven attribution uses machine learning to share it among the clicks. These are the only two models Google Ads still supports: first click, linear, time decay and position-based were retired.
The shares of one order always add up to one. In Google Ads, each conversion action has its own model setting. GA4 has one model for the whole property: data-driven or last click across paid and organic channels, or last click across Google paid channels only. Changing it also recalculates past conversion and revenue reports.
The store’s own records count each order once, with no model. Google Ads shows only the credit given to Google’s own ads. If another ad platform also claims the order, the two reports together show more orders than the store took. How Google Ads, GA4 and your shop count the same sale shows which number suits which decision.
Where you see it
- In Google Ads, the Attribution model setting of each conversion action (Goals → Summary → the action → Edit settings).
- In GA4, the reporting attribution model under Admin → Data display → Events → Attribution settings.
Example
Example store, not client data.
A customer clicks the tableware shop’s Shopping ad, two days later its search ad, then orders a set for 600. Under last click, search gets 1 conversion worth 600 and Shopping gets 0. If data-driven attribution splits the credit 0.6 to 0.4, Shopping gets 0.6 conversions worth 360 and search gets 0.4 worth 240. Either way, the two campaigns add up to 1 conversion worth 600.
Not to be confused with
- Conversion window — how many days after a click a conversion still counts. The model shares credit among the clicks inside that window.
- MER — total revenue over total marketing spend. It needs no model, because it does not split orders by channel.
Right and wrong readings
- Wrong: “After the switch to data-driven, Shopping got more conversions, so sales grew.” Right: credit moved between campaigns, and the number of orders stayed the same.
- Wrong: “Google Ads and GA4 show different numbers, so tracking is broken.” Right: they can apply different models, windows and channels to the same orders.
Sources
- About attribution models — Google Ads Help: last click and data-driven, retired models, setting per action. Checked 2 October 2026 (archived copy of 30 July 2026).
- Get started with attribution — Analytics Help: the three GA4 models, attribution settings. Checked 2 October 2026 (archived copy of 18 September 2026).
- AttributionModel — Google Ads API: last click and data-driven. Checked 2 October 2026.
- ConversionAction — Google Ads API: model and window per action. Checked 2 October 2026.
- AttributionSettings — Google Analytics Admin API: the three models; changes apply to past data. Checked 2 October 2026.