What is a Position-Based Attribution Model?

By default, the position-based attribution model assigns 40% of the conversion credit to the first interaction, 20% of the conversion credit to the middle interactions and 40% of the conversion credit to the last interaction on a conversion path. 

If you have a business model or advertising objectives which values first and last interactions much more than the middle interactions then you can use the position-based attribution model.

How the conversion credit is calculated for the position-based attribution model?

The following examples will help you in understanding how the conversion credit is calculated in the case of the position based attribution model. 

Consider the following conversion path with a path length of four:

This conversion path can also be represented by the following data table:

Under the position-based model, both the first interaction and last interaction get 40% of the credit for conversion and the remaining 20% conversion credit is equally divided among the middle interactions. 

So the conversion credit distribution would look like the one below:

• Campaign A gets 40% credit for the conversion.
• Campaign B gets 20% credit for the conversion.
• Campaign C gets 40% credit for the conversion.

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Consider the second conversion path with a path length of three:

This conversion path can also be represented by the following data table:

Under the position based model, the conversion credit distribution would look like the one below:

• Campaign A gets 60% (20%+40%) credit for the conversion.
• Campaign B gets 40% credit for the conversion.
• Campaign C gets 0% credit for the conversion (as campaign C is not on the conversion path)

The total conversion credit for campaign A so far 

= (conversion credit for campaign A on the first conversion path + conversion credit for campaign A on the second conversion path) / 2 

= (40% + 60%) / 2 

= 50%

Total conversion credit for campaign B so far 

= (conversion credit for campaign B on the first conversion path + conversion credit for campaign B on the second conversion path) / 2 

= (20% + 40%) / 2 

= 30%

Total conversion credit for campaign C so far 

= (conversion credit for campaign C in the first conversion path + conversion credit for campaign C in the second conversion path) / 2 

= (40% + 0%) / 2 

= 20%

Consider the third conversion path with a path length of two:

This conversion path can also be represented by the following data table:

Under the position-based attribution model, Campaign A gets 40% credit for the conversion and campaign B gets 40% credit for the conversion. 

Since there are no middle interactions, the remaining credit of 20% is equally divided between campaigns A and campaign B.

• Campaign A gets 50% (40% + 10%) credit for the conversion.
• Campaign B gets 50% (40% + 10%) credit for the conversion.
• Campaign C gets 0% credit for the conversion (as campaign C is not on the conversion path).

The conversion credit distribution would look like the one below:

The total conversion credit for campaign A so far 

= (conversion credit for campaign A on the first conversion path + conversion credit for campaign A on the second conversion path + conversion credit for campaign A on the third conversion path) / 3 

= (40% + 60% + 50%) / 3 

= 50%

The total conversion credit for campaign B so far 

= (conversion credit for campaign B on the first conversion path + conversion credit for campaign B on the second conversion path + conversion credit for campaign B on the third conversion path) / 3 

= (20% + 40% + 50%) / 3 

= 36.67%

The total conversion credit for campaign C so far 

= (conversion credit for campaign C on the first conversion path + conversion credit for campaign C on the second conversion path + conversion credit for campaign C on the third conversion path) / 3 

= (40% + 0% + 0%) / 3

= 13.33%

If we assume that there are only three conversion paths in our selected time period, then the sum of conversion credit for campaigns A, B and C under the position-based model would be:  50% + 36.67% +13.33% = 100% 

Since the sum of the conversion credit for three campaigns is 100%, this proves that our conversion credit calculations are all correct. 

Other articles on Google Analytics Attribution Models

1. Last Interaction Attribution Model in Google Analytics Explained
2. First Interaction Attribution Model in Google Analytics
3. Linear Attribution Model in Google Analytics
4. Time Decay Attribution Model in Google Analytics
5. Last Non-Direct Click Attribution Model in Google Analytics
6. Last Google Ads Click Attribution Model in Google Analytics
7. Data-Driven Attribution Model in Google Analytics – Tutorial
8. Learn to set up Data-driven attribution model in Google Analytics
9. Default & Custom Google Analytics Attribution Models Explained
10. Which Attribution Model to use in Google Analytics?
11. How to Create Custom Attribution Model in Google Analytics