Historically, Google Analytics defaulted to Last Click attribution for most clients. With the introduction of GA4, this default shifted to the Data-Driven Attribution (DDA) model. While DDA provides a broader perspective of the customer journey, it's essential to understand its nuances and potential gaps, especially when compared with the Last-click approach. This change can lead to significantly different interpretations of channel performance and misreporting of metrics and attribution. It is important to note that DDA also has significant challenges measuring the touchpoints and attribution of non-Google channels (including email, social, and/or affiliate).

Understanding DDA

DDA leverages a weighting system to distribute credit: combinations that were more important toward driving a conversion are weighted more heavily, and less important combinations are weighted less. It places high value on touch points, according to Google “DDA uses machine learning algorithms to evaluate both converting and non-converting paths. The resulting Data-driven model learns how different touchpoints impact conversion outcomes.”

Problems with GA4 + DDA with Non-Google Channels

Issue 1: Recognied Gaps in the DDA Mode

Google's own documentation acknowledges situations where the DDA model might fall short:

• Minimum Conversion Thresholds: For DDA to effectively assess the value of a specific conversion path, it needs a minimum of 400 conversions for that unique path within 30 days. If this benchmark isn't met, the paths are disregarded in DDA, even though Google admits these paths are valid. The rationale is that without this data, the DDA model can't achieve statistical significance for the said path.
• Increased Touchpoints, Decreased Significance: With GA4, the number of touchpoints has been substantially expanded. This increment in potential paths makes it challenging for any specific path to achieve the required 400+ conversions, especially when compared to earlier GA versions. For instance, CJ ran an analysis of data from over 1,200 clients indicated that roughly 98% of affiliate conversion paths would be excluded based on Google's criteria. In this analysis, only about 1.4% of paths that had an affiliate interaction saw 400+ conversions.

Issue 2: Possible Bias Toward Google Channels

There's a potential for Google-owned channels to receive more attribution value in DDA. The reason is twofold:

• Extensive Data Collection: Google naturally has access to more comprehensive data on interactions related to its own channels.

• Measurement Bias: Features within GA4 may provide a more consistent and preferential measurement of interactions with Google channels compared to non-Google channels.

Challenges in Drawing Comparisons:

If you utilized DDA in previous Google Analytics versions, drawing a direct comparison with GA4's new methodology is impossible. The alterations introduced by Google mean that comparing data between the two versions will lead to significant discrepancies in reporting.

If your previous version of Google Analytics was set to Last Click:

Ensure your current GA4 settings are also set to Last Click. Simply login to Google Analytics, select Admin > Attribution Settings, and set your attribution model and conversion window to “last click.”

GA4’s Last Click view may still show discrepancies between non-Google platform reporting and their reporting, but the last-click attribution method is less likely to misreport and paint a better picture of your campaign performance.

Conclusion

While GA4 and its DDA model promise a more nuanced understanding of user journeys, it's crucial for users to recognize the potential inaccuracies and biases inherent in the system. Making informed decisions requires an understanding of these nuances and the implications they might have on reporting.

If you are running a SafeOpt campaign, here is where you can find the reporting in GA4.

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