If you run ads on Google and your site has visitors from Europe, Consent Mode affects what you can measure and which advertising features are available to you. It is not just a matter for your developer.
Consent Mode is the way your site tells Google's tags what the visitor accepted in the cookie banner. The banner collects the choice. Consent Mode passes it on to Google Analytics, Google Ads and Google's other tags, so they can adjust how they work.
The four parameters
Each parameter takes the value granted (allowed) or denied (not allowed). There are four main ones:
- ad_storage: whether storing data, such as cookies, for advertising purposes is allowed.
- analytics_storage: whether storing data for analytics is allowed, for example for the duration of a visit.
- ad_user_data: whether user data may be sent to Google for advertising purposes.
- ad_personalization: whether personalised advertising, such as remarketing, is allowed.
The last two were added at the end of 2023, and they are what makes v2 different. For personalised advertising, both must be granted. If your site set up Consent Mode some time ago, it may only send the first two and need an upgrade.
Why it matters if you have visitors from the EEA
Since March 2024, Google has asked anyone using its advertising services to send consent signals for users in the European Economic Area. Its documentation mentions the same need for the United Kingdom and Switzerland.
Without these signals, features such as audience lists for personalised advertising, and part of the measurement, do not work for these users. In practice, your campaigns see less than what is actually happening, and automated bidding strategies work with less conversion data.
Consent Mode does not replace consent. It passes the visitor's choice on to Google's tags.
If the visitor says no, the tags must respect that choice. What changes with Consent Mode is that Google knows what the choice was and works within those limits.
Basic or advanced implementation
In a basic implementation, Google's tags do not load at all until the visitor responds to the banner. If they decline, nothing is sent to Google, not even the consent status. To estimate the conversions that are lost, Google then uses a general model.
In an advanced implementation, the tags load from the start with a default of denied. If the visitor declines, they send signals without cookies (cookieless pings), with information such as the time, the browser, the referring page and the consent status. Google uses them in a model specific to your own account, which gives a more detailed estimate.
The advanced implementation gives you more data, but it means some communication with Google takes place even without consent. This must be described in your cookie policy, and the choice between the two is worth making together with your legal adviser. This article is a practical guide, not legal advice.
What to check on your site
- The default state is set before any Google tag loads.
- The banner sends an update as soon as the visitor makes a choice, and again whenever they change their mind in the cookie settings.
- All four parameters are sent, not just the two old ones.
- With Google's Tag Assistant you can see what is sent before and after the visitor's choice.
- If you use a consent management platform (CMP), confirm that it supports Consent Mode v2.
- Google Ads and Google Analytics 4 show indicators of the status of your consent signals. Check them after every change to the site.
On the THPAUL website, for example, tags load only for the categories the visitor accepts, using Consent Mode v2, and the choice can be changed from “Cookie settings” at the bottom of every page.