Attribution in Google Analytics refers to assigning credit for a specific conversion or user action to a particular marketing channel or touchpoint within a conversion path. Attribution models allow us to understand which marketing channels and campaigns contribute the most to our business goals so that we can optimize our marketing strategies accordingly.
By default, Google Analytics uses a last-click attribution model that assigns 100% of the credit for a conversion to the last touchpoint a user interacted with before converting. However, other attribution models are available that consider multiple touchpoints in the user journey, such as the first-click, linear, and time decay models.
In Google Analytics 4, the default is the so-called cross-channel data-driven attribution, which attributes conversions based on how people engage with different ads and make purchase decisions. It uses user behavior data to determine which keywords, ads, and campaigns impact conversions most. Google Analytics thus “breaks down” conversions into smaller parts within the conversion path and assigns e.g. 1 conversion to 3 sources in the ratio 0.4 + 0.4 + 0.2.
Example of a conversion path:
Google search > Facebook remarketing > Affiliate > PURCHASE
Universal Analytics (last click) conversions
Google = 0
Facebook = 0
Affiliate = 1
Google Analytics 4 (data-driven) conversions
Google = 0.3
Facebook = 0.1
Affiliate = 0.6
It was not possible to set up an attribution model in Universal Analytics (UA). Last click was the default attribution model. However, in GA4, we can choose from 7 attribution models so far. We can also compare the data between the models. Therefore it is important which model we choose. The differences can be significant.
