Since implementing Consent Mode v2, I see a drop in Google Ads traffic
It’s common for marketers to notice a significant drop in traffic in GA4 after implementing Consent Mode v2, particularly in traffic from Google Ads. This often raises questions: is something wrong with the data? Or have the campaigns become less effective?
After implementing consent processing in GA4, a drop in visitors is always observed. This includes visitors who decline cookies (often around 10%) and visitors who leave the site without even interacting with the cookie banner (this can be a significant percentage, depending on the type of site and how well the marketing campaign aligns with the landing page).
Google requires approximately 8 weeks to get consent modeling fully operational. Typically, after 8 weeks, an increase in visitor data becomes visible in GA4. Through cookie-less pings, Google can estimate how many visitors have been on the site. For instance, if Google identifies 1,000 visitors and 600 have given consent, GA4 can proportionally attribute the remaining 400 visitors to the same channels. If 300 out of those 600 visitors (50%) come from Google Ads, 200 out of the 400 missing visitors (50%) will also be attributed to Google Ads.
There is a known bug in Google Ads and GA4 involving UTM parameters: https://www.adpage.io/post/google-ads-campagnenamen-bugfix. Forgetting to include UTM parameters—often because it wasn’t previously required—is frequently the primary reason why a channel group in GA4 underperforms after a Server-Side Tagging (SST) implementation.
It’s also possible that consent processing within Google Tag Manager has not been set up correctly. This blog article explains why proper setup is crucial and how to configure it correctly: https://www.adpage.io/post/cmp-instellen-via-gtm-icm-sst.
After implementing consent processing in GA4, a drop in visitors is always observed. This includes visitors who decline cookies (often around 10%) and visitors who leave the site without even interacting with the cookie banner (this can be a significant percentage, depending on the type of site and how well the marketing campaign aligns with the landing page).
Google requires approximately 8 weeks to get consent modeling fully operational. Typically, after 8 weeks, an increase in visitor data becomes visible in GA4. Through cookie-less pings, Google can estimate how many visitors have been on the site. For instance, if Google identifies 1,000 visitors and 600 have given consent, GA4 can proportionally attribute the remaining 400 visitors to the same channels. If 300 out of those 600 visitors (50%) come from Google Ads, 200 out of the 400 missing visitors (50%) will also be attributed to Google Ads.
There is a known bug in Google Ads and GA4 involving UTM parameters: https://www.adpage.io/post/google-ads-campagnenamen-bugfix. Forgetting to include UTM parameters—often because it wasn’t previously required—is frequently the primary reason why a channel group in GA4 underperforms after a Server-Side Tagging (SST) implementation.
It’s also possible that consent processing within Google Tag Manager has not been set up correctly. This blog article explains why proper setup is crucial and how to configure it correctly: https://www.adpage.io/post/cmp-instellen-via-gtm-icm-sst.
Updated on: 22/11/2024
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