An attribution rule that gives all the credit for a sale to the last eligible click before it. Many affiliate programmes use it.
A shopper can meet several publishers before buying: a review on Sunday, a cashback site on Tuesday, a voucher site at checkout on Thursday. Under last click, the commission goes to the last eligible affiliate click within the cookie window, so a later click from another publisher takes the credit from an earlier one.
That makes the end of a purchase valuable. A click on a search for your name, on a search for a code, or on an extension's offer at checkout can be credited with a sale that was already on its way. Often that's exactly what the brand chose to pay for. Whether it's allowed is for the programme terms, and some programmes de-duplicate against the brand's own channels, so no commission is due when the brand's own ad or email won under its rules.
- In Google Ads, the Last click model gives all the credit for a conversion to the last-clicked ad and keyword. Data-driven is the default for most conversion actions, and the first click, linear, time decay and position-based models are no longer supported.
- In GA4, a session is filed in the Affiliates channel only when its medium is
affiliate.
So your network, Google Ads and GA4 can each credit one order to a different place. How a sale gets credited lines them up.
Google's own help and policy pages first.