Affiliate marketing in GA4

Since the decommissioning of UA (Universal Analytics) in Google Analytics (GA), to GA4, many marketers have reported higher discrepancies with their affiliate platform reporting.

It's important to understand that these discrepancies do not reflect negative changes in the affiliate activity or performance. The differences result from a different logic with which GA4 works.

Firstly what is GA4: GA4 is the 4th version of Google Analytics and it has replaced Universal Analytics. One of the key differences between UA and GA4 is the move from tracking page views or visits to tracking events and the use of data-driven attribution. The new analytics allows for universal tracking of mobile app and website usage, previously these were separate in GA.

Data driven attribution (DDA) uses machine learning to assign credit to the touch-points that contributed to a conversion. This is used by default in GA4, however you can configure other attribution models. You can read what Google explain about their model here. One point to note is the actual algorithm is not shared publicly and results are also unique to each advertisers, therefore we can't determine what impact this may have on what is reported in the affiliate (and other marketing) channels.

A few key things to note:

  • Under reporting of revenue from non Google sources in GA4 has been reported by marketers widely (this is not unique to the affiliate channel or platform)
  • DDA model is being used by default in GA4 (but you can reconfigure this)
  • Google's DDA model was designed for Google related products (see their support documentation here).
  • Automated tagging is possible with Google products but manual UTM tagging required to be set up for other channels.
  • It has been reported by marketers that large amounts of traffic is being reported as "direct" - this has been found to be due to cookie consent banners (high prevalence of issues with the Shopify cookie banner) GA4 records the visit on the second page view after the consent and therefore data on the marketing channel that drove the visit are lost
  • While you may have observed a shift in GA4 metrics, the tracking and attribution methods employed by Commission Factory remain unchanged

What can you do to help alleviate the discrepancy:

  1. Use Last Click Attribution: GA4 allows you to change the attribution model from DDA to a Last Click model. This model attributes the conversion to the last touchpoint the customer interacted with before making a purchase, the same as your affiliate marketing activity. To adjust this, you can log in to Google Analytics, navigate to Admin > Attribution Settings, and adjust your attribution model and conversion window to “last click”. This method is more reliable and less prone to misreporting than DDA, especially for non-Google channels like affiliates.
  2. Implement UTM Parameters correctly: Utilize UTM parameters on your affiliate links. By properly tagging affiliate links with UTM codes, you can track these interactions more accurately in GA4. Make sure to consistently use UTM parameters for source (utm_source), medium (utm_medium), and campaign (utm_campaign). Ensure you change settings to Allow manual tagging (UTM values) to override auto-tagging (GCLID values). Update your UTM parameters for affiliate traffic in your Commission Factory account under Settings - Tracking rules
  3. Investigate and identify where some discrepancies may come from and troubleshoot. For example your cookie consent banner, cookie run time, how you have configured your GA4 set up.
  4. Consider adding the [AffiliateId] Shortcode to your Click Append (CF UTM) Parameters. By receiving the information in GA on a per affiliate basis, it may be helpful to note which partners you are seeing a discrepancy with. This could be due to the method of how the partner promotes your brand in relation to Google's recent changes with some partners seeing more discrepancy than the average.  
  5. Avoid hastily canceling transactions or discrediting marketing channels solely due to discrepancies. Prematurely canceling transactions can result in missed opportunities, lost sales, and potential harm to relationships with your affiliate partners.

We appreciate that Google Analytics is a strong tool that allows merchants to review multiple channels and plan budget allocation and perform forecasting, however it is important to review alongside Commission Factory data as this is how spend for the Affiliate Channel is determined. 


As more users switch to GA4 we will endeavour to provide more information and provide updates as we learn more about these changes from Google over time.