Google Analytics 4 (GA4) has Item List & Promotion reports. But – unlike GA3 Enhanced Ecommerce, no revenue or conversions are attributed back to Promotion or Item Lists (at the time of writing).

As Simo Ahava wrote in October 2020 about GA4 Product List Attribution;

It would be odd to have product lists as a data type without them actually having any functionality.

But here we are — more 2 than years later. Neither promotion or item lists have any functionality. In a help text from Google Analytics we find this information:

If you want to measure when someone makes a purchase after they view or click a promotion, make sure to add at least one of the parameters — promotion_id or promotion_name — to every subsequent ecommerce event.

Google Analytics apparently ticked the box DONE for GA4 Item List & Promotion attribution with that sentence. At the time of writing, it’s totally unclear if GA4 will get this functionality within the tool, but it doesn’t look like it.

I don’t understand some of the choices and priorities Google Analytics makes for GA4, but instead of just ranting, here is my solution.

My solution is GA4 – Item List & Promotion Attribution for Server-side GTM (SGMT) & Web GTM. The attribution is a combination of a Google Tag Manager Template Variable, GTM Setup & correct implementation. The following functionality are offered:

• Last Click Attribution
• First Click Attribution
• Can attribute Item List, Promotion & Search Term
• Reset/delete Attribution Data after Purchase
• Attribution Time (for how long should Item List, Promotion or Search Term be attributed)
  • Attribution Time can be either GA4 Session or Custom Attribution Time

Although this GA4 Item List & Attribution solution has more attribution options than Enhanced Ecommerce has, this solution isn’t for everyone. It’s technical, and requires at least GTM (Web).

Differences between doing the attribution with GTM (Web) vs. Server-side GTM are listed below.

Functionality	GTM (Web)	Server-side GTM
Cross (sub)domain tracking	No *	Yes
Server to Server-side (Measurement Protocol)	No	Yes
Attribution/processing	Users browser	Server-side
Storage Limitation	Yes	No
Costs Money	No	Yes

About the GA4 Item List & Promotion Attribution solution

As mentioned, the solution is both for Server-side GTM and Web GTM. Templates and setup are described in detail on Github:

• GA4 – Item List & Promotion Attribution for Server-side GTM
• GA4 – Item List & Promotion Attribution for Web GTM

Both the Server-side GTM & GTM (Web) Variable are identical in functionality, but since the storage solutions available in SGTM & GTM (Web) are different, the setup is different.

Attribution

Attribution happens on 2 levels:

1. Event-level
   • Promotion without Items
   • Search Term
2. Item-level
   • Implemented Items data (ex. Item List Name) trumps attributed Items data. Ex. if you are adding a Item to cart directly from a Item List, the implemented Item List Name will be used. If you are adding the Item to cart from a product page (without Item List), the attributed Item List Name will be used.

• Item-level trumps Event-level
  • Promotion without Items will not be attributed when Promotion with Items are attributed

Some final words

A random dude shouldn’t have to make this solution, GA4 should be able to do this “out of the box”. But at least, those who need GA4 Item List & Promotion Attribution, they now have an alternative.

Both Templates have been submitted to the Google Tag Manager Template Gallery, but at the time of writing, only the Server-side GTM version is available in the Template Gallery.

Winner of the Golden Punchcard Prize

Unofficial solution from Google

Some days ago, a Web GTM setup + Template called GA4 Ecom Attributor was published on the Google Github. This is not an officially supported Google product, but it’s made by someone in Google. It uses cookies for attribution. To me this is just another indication that GA4 Item List & Promotion attribution will not be supported out of the box for Google Analytics 4.