What is Attribution?

Attribution is assigning credit to the marketing channels and touchpoints that contributed to a conversion. Without attribution you do not know which channels really drive growth, and you cannot divide your budget effectively.

Attribution models

Last click: all the credit goes to the last channel before the conversion. First click: all the credit goes to the first touchpoint. Linear: credit is divided equally over all touchpoints. Time decay: more credit goes to touchpoints closer to the conversion. Data-driven: GA4 and Google Ads divide the credit automatically, based on the actual contribution, using machine learning. Since 2023, GA4 and Google Ads only offer data-driven and last click; first click, linear and time decay are no longer available there.

Attribution in GA4

By default, GA4 uses data-driven attribution across all channels. This is more accurate than last click, but it works best with enough conversion data. Use UTM tags consistently so every channel is labelled correctly in your reports.

Attribution and budget allocation

Last click overestimates direct conversion channels such as branded search and underestimates top-of-funnel channels such as display and social media. Data-driven attribution gives a fairer picture for strategic budget decisions.

Is attribution always 100% accurate?

No. Cross-device behaviour, ad blockers and privacy restrictions make perfect attribution impossible. Use it as a guide, not as the absolute truth.

Which attribution model should I use?

Data-driven attribution in GA4 is the best choice if you have enough conversion data. More at developers.google.com/search.