Navigating GA4 changes – explaining what they mean for Awin advertisers

One of the biggest changes to affect the affiliate channel with Google Analytics 4 (GA4) is the transition from the last-click model found in Universal Analytics (UA), to the data-driven attribution (DDA) model set in GA4 by default.  

The differences between GA4 and UA 

Whilst the move to a data-driven model has some synergy with Awin's own reporting philosophy (as highlighted by the acquisition of the SingleView multi-touch attribution platform), there are a number of changes affiliate marketers should consider when using GA4 to optimise their channel.  

Algorithmic attribution vs last-click - UA took a simple approach to tracking sales, where the last (non-direct) click in a converting journey was given 100% credit for the sale and associated revenue. GA4 utilises a proprietary attribution model which uses machine learning algorithms to understand how different touchpoints impact a conversion. Each touchpoint involved in the conversion is then attributed a proportion of the sale and revenue, with the percentage awarded being determined by a data-driven model.  

A data-driven model - GA4 uses a data-driven model to determine the credit rewarded to touchpoints involved in a conversion that includes factors such as; time from conversion, device type, number of ad interactions and many more. While data-driven models by nature are a ‘black-box’, a number of these determining factors in the GA4 algorithm will only be trackable through media that circulated through a Google source. This means there will be a bias towards this media, and affiliate managers (and any managers of channels not run through Google) need to keep this in mind when viewing performance through the data-driven model.  

Additionally, GA4 requires a minimum of 400 conversions of a unique path to enable a given publisher to be included in the DDA model. It is common that a minimum threshold is required to build an accurate model, however this does present a challenge for many affiliate programmes with their broad range of long-tail publishers that will, by default, be excluded from the model. 

The conversion window - UA would previously only consider the last four interactions in any of its attribution models. With GA4, the model factors in the last 50 touchpoints in a conversion path. For conversion events, users can choose between a 30, 60 or 90-day lookback window. Affiliate marketers should ensure that their lookback window within their affiliate platform matches the setting in GA4 for parity, to avoid GA4 showing involvements not tracked by their platform. 

Event tracking - Another big change for GA4 is the way that engagement is tracked whilst on-site. In UA, user interactions were tracked via page views. In GA4, advertisers can add up to 25 event parameters such as video watches and clicks on specific properties. As best practice, Google recommends advertisers create a new set of event parameters that they use to measure user engagements. Affiliate advertisers can use this data to understand if there are potential trouble spots on affiliate landing pages that can result in leakage, or negatively impact conversion.  

Additionally, it's important to note that you can select to view performance by all or some of the events. Ensuring that you only select 'Conversion' will avoid showing reports that have additional actions included, not representing the core goal you are trying to review.  

The impact of GA4 on affiliate marketing 

Changing to a different attribution methodology (regardless of implementation) will ultimately shake things up somewhat. At Awin, we’ve anecdotally seen GA4 accounts where affiliate is generally unaffected, however, there are cases where the channel definitely is.   

Whilst there will always be differences in volumes tracked between two different tracking platforms, affiliate advertisers can expect to see greater variations in the performance shown in GA4 vs the performance reported via their affiliate platform. This will be especially prevalent for publishers which predominantly operate in the lower funnel, such as incentive sites. Where sales they drove were previously credited solely to them in UA, they are now shared with all other touchpoints in the path to conversion, so will inevitably show a lower volume of sales and revenue. 

Broadly with GA4, you tend to see certain channels or segments thrive or suffer based on the website’s overall channel and marketing mix. For example, a client who heavily invests in branded search as a proportion of their overall marketing mix, may see paid social suffer under a particular model. But this doesn’t necessarily mean paid social is performing badly. Or a client who has a longer consideration period may see affiliate suffer, vs those that have a shorter period. 

Validating sales using GA4  

Advertisers have often used Google Analytics in conjunction with internal sales data to validate sales. However, advertisers should now not be validating affiliate sales against the data in GA4 – attributed data should be taken as insight to provide a holistic and strategic overview of how their marketing mix is performing. It shouldn’t be used to approve or deny payment, especially when other channels (Google Ads, FB etc) get paid per-click whether or not they drive conversions.  

If advertisers optimise their spend entirely on the best performing channels shown by GA4, they’d end up cutting all spend outside of Google owned channels, which the data is biased towards. 

The introduction of attribution modelling in GA4 also means that the default view won't enable a view of the last touchpoint before conversion. Whilst you can use the 'last-click' model to view performance, we would strongly recommend reviewing your tracking setup with Awin to ensure you have de-duplication set up to validate affiliate involvement at the point of conversion. This way you can avoid the need to rely on GA4 to validate sales, simply using your internal sales data to verify an order status and accept or decline commissions. More information about how to set up best practice de-duplication can be found here. 

If you have any questions relating to GA4 and its impact on affiliate attribution at Awin, please get in touch with the team.