GA4 Consent Mode and modelled data

In the EU, Google Analytics needs consent before it sets cookies. Consent Mode is Google's answer to the visitors who say no: instead of losing them entirely, GA4 adjusts what it collects and, in some cases, estimates what it did not see.

How Consent Mode works

The site tells Google's tags whether the visitor accepted analytics and advertising cookies.

• Basic mode: if the visitor declines, the tags do not load at all. Nothing is sent about that visit.
• Advanced mode: the tags load anyway and, without consent, send cookieless pings: a page was viewed, an event happened, without the identifiers a cookie would provide.

What "modelled" means

From those pings and from the visitors who did accept, GA4 can use machine learning to estimate the behaviour of the visitors who declined, and fill in reports with that estimate. Google calls this behavioural modelling for users and conversion modelling for conversions. It only runs when a property has enough data, and the result is an estimate, not a count.

Why it matters

• Numbers become partly estimated. A conversion count may include conversions that nobody measured, only predicted.
• Comparisons get harder. A change in the consent rate or in Google's model shifts numbers even when your traffic did not change.
• Advanced mode still sends data without consent. Whether those cookieless pings are acceptable without consent is a question for your lawyer, not for a tag setting; regulators in several EU countries look at what is sent, not only at cookies.

Reading GA4 with Consent Mode

• Check whether your property uses modelled data (GA4 shows a notice in the reporting identity settings).
• Compare trends, not absolute numbers, across periods with different consent rates.
• For decisions based on small numbers, prefer measured data.

The cookieless alternative

A tool that sets no cookies and stores no personal data can measure every visit without a consent request, so there is nothing to model. The numbers are counts, not estimates. That is the approach Statsdot takes: see Cookieless analytics. Whether your site still needs a banner depends on everything else it loads.