Consent Mode V2 Setup | Measurement With Consent

Consent Mode is the mechanism that communicates a user’s cookie choice to Google’s tools. When a user declines measurement, tags do not simply go silent — they keep sending signals that contain no personal data.

Why it is needed

Putting up a consent banner is not enough on its own; the decision that banner captures has to reach the measurement tools. On many sites the banner appears while tags keep firing regardless — both a legal problem and a false sense of security.

The opposite mistake is common too: shutting down all measurement when consent is refused. In that case part of your traffic becomes entirely invisible and reports fall below reality.

What happens when consent is refused

Set up correctly, Consent Mode sends cookieless signals when consent is not given. These signals do not identify an individual but let Google model total conversions.

So even with a low consent rate your conversion picture does not go blank; the missing part is filled by modelling. Modelling needs a certain data volume to work — on very low-traffic sites this layer does not engage.

The order of setup

The right order is: install the consent banner and configure it to store the user’s choice, pass that choice to Google Tag Manager, then configure tags to fire according to consent state.

The most frequently skipped step is the link between banner and GTM. The banner is installed, the tags are installed, and the two know nothing about each other. In that state neither the legal requirement is met nor does modelling work.

Verification

After setup it is always tested: do tags fire when consent is granted, do cookieless signals go out when it is refused, does behaviour change when the preference is updated. GTM preview mode and browser developer tools are enough for this check.

Google Ads and GA4 also report consent status in their interfaces. Warnings there are the fastest sign that setup is incomplete.

How do we start? First I test whether your existing banner actually talks to your tags. I send the gaps and the setup order in writing. You can reach me from the contact page.

Frequently Asked Questions

Is this setup mandatory outside Europe?

If you advertise to Europe it is mandatory on Google’s side; even if you do not, privacy law in most jurisdictions requires consent management. And the modelling benefit improves measurement quality regardless of the legal requirement.

Which consent banner should I use?

One that documents compatibility with Consent Mode. What matters is not the brand but whether it converts the user’s choice into the correct signal — I verify that by testing after setup.

What if my consent rate is low?

Banner design affects the rate directly: banners that clearly state what consent is for and make choosing easy get higher rates. Obtaining consent by misleading users, on the other hand, is a separate risk.