Google Consent Mode v2 and Cookiebot: why does Analytics show fewer visitors?
- When a visitor does not accept cookies, Analytics does not get the usual data about them. That is why the numbers drop.
- Consent Mode v2 is Google’s way of respecting the visitor’s choice while still modelling the missing data.
- Advanced mode retains more information than basic mode but requires a careful implementation.
If your Google Analytics visitor numbers dropped after introducing a cookie banner, measurement is probably working exactly as it should. Visitors who do not give consent do not appear in standard reports. With Consent Mode v2, part of this information can be modelled back. This article explains how.
What is Consent Mode v2?
Consent Mode is Google’s mechanism that lets a website tell Google’s tags what the visitor has consented to. Version 2 added two new signals: ad_user_data and ad_personalization. Google requires them in the European Economic Area if you want to use ad targeting and remarketing.
Basic or advanced?
| Basic | Advanced | |
|---|---|---|
| Tags before consent | Do not load at all | Load, but do not store cookies |
| Data from visitors who decline | None | Cookieless signals for modelling |
| Modelled data | Limited | More comprehensive with enough traffic |
| Implementation | Simpler | Requires careful configuration |
In advanced mode Google receives cookieless pings from visitors who decline, which are used to model missing visits and conversions. Modelling requires enough traffic, so on a small site the difference may be small.
Common mistakes in Cookiebot implementations
- Tags fire before consent: for example Hotjar or the LinkedIn pixel is loaded in Tag Manager without a consent condition.
- The default state is missing: if default consent is not set before the tags load, Consent Mode does not work correctly.
- Old tags are forgotten: for example an old Universal Analytics tag or duplicate GA4 properties.
- Optimisation plugins break the banner: caching and optimisation plugins can move the Cookiebot script to the wrong place.
Read what marketing technology means for an SME or see our marketing technology service. We are happy to review your implementation.
FAQ
Why does Google Analytics show fewer visitors after adding a cookie banner?
Visitors who do not accept analytics cookies do not appear in standard data. In the advanced mode of Consent Mode v2, part of the missing data can be modelled.
Is Consent Mode v2 mandatory?
Google requires it in the European Economic Area if you want to use ad targeting, remarketing and conversion modelling in Google Ads.
Does Cookiebot work with Consent Mode v2?
Yes. Cookiebot passes consent signals to Google’s tags when the integration and the default state are configured correctly.
