What is Consent Mode?
Consent Mode is a technical solution developed by Google that adapts the behavior of tracking tags (Google Ads, GA4, Floodlight) according to the consent choice expressed by the user through the cookie banner. Consent Mode allows advertisers to continue partially measuring their advertising performance even when users refuse cookies, thanks to anonymized signals and conversion modeling.
How does Consent Mode work?
Consent Mode relies on consent states transmitted by the consent management platform (CMP) to Google tags, primarily analytics_storage (audience measurement) and ad_storage (advertising), supplemented since version 2 by ad_user_data and ad_personalization.
Two types of behavior are then possible. If the user gives consent, the tags operate normally with cookies. If the user refuses, Consent Mode adjusts their behavior: in advanced mode, the tags send anonymous pings (without cookies or user identifiers) that support modeling; in basic mode, no data is sent before consent is given.
Based on these anonymized signals, Google applies a statistical model (machine learning) to estimate conversions from users who have not given consent, relying on the behavior observed among users who have consented. The modeled conversions then appear in Google Ads and GA4 reports, without any visual distinction from observed conversions.
Why is Consent Mode important in marketing?
In France, a significant proportion of users refuse cookies through consent banners – often 30% to 50% depending on the industry and the design of the CMP. Without Consent Mode, these visitors become invisible: conversions are not measured, ROI is underestimated, and bidding algorithms receive insufficient data. Since March 2024, Consent Mode v2 has also been mandatory for using Google remarketing and audiences within the European Economic Area.
The issue goes beyond compliance: more complete measurement enables better budget allocation. TrackAd clients who improve the reliability of their data collection and attribution achieve an average 21% increase in ROI within 2 months, precisely because their decisions are based on comprehensive data rather than an incomplete view.
Consent Mode at TrackAd
TrackAd integrates Consent Mode data into its cross-channel reconciliation layer: observed and modeled conversions reported by advertising platforms are compared with actual back-office transactions in order to quantify consent-related discrepancies and correct attribution. For TrackAd’s 150+ clients in France and internationally, 100% of useful data is collected and automatically updated every day, regardless of the cookie refusal rate.
Frequently Asked Questions
What is the difference between Consent Mode and a CMP (consent management platform)?
A CMP (Axeptio, Didomi, OneTrust, etc.) displays the cookie banner, collects the user’s choice, and stores it. Consent Mode, on the other hand, transmits this choice to Google tags and adapts their behavior accordingly. The two are complementary: the CMP collects consent, while Consent Mode technically applies it to Google tracking.
What is the difference between basic and advanced Consent Mode?
In basic mode, no Google tag is triggered until the user has given consent: no data is sent, and the modeling is less accurate. In advanced mode, the tags send anonymous pings even when consent is refused, which improves the quality of conversion modeling. However, the CNIL has expressed reservations regarding the compliance of advanced mode.
Does Consent Mode work without cookies?
Yes, that is precisely its purpose. When a user refuses cookies, advanced Consent Mode sends signals without cookies or identifiers: these anonymous pings allow Google to statistically estimate missing conversions. Measurement is therefore not observed individually but modeled at an aggregated level.
Is Consent Mode v2 mandatory?
Yes, for advertisers targeting the European Economic Area: since March 2024, Google has required Consent Mode v2 (with the ad_user_data and ad_personalization signals) to continue using remarketing, audiences, and advanced measurement in Google Ads. Without it, European audience lists stop being populated.
How many conversions can Consent Mode recover?
Google states that modeling can recover a significant proportion of conversions lost due to consent refusal – the commonly reported estimate is approximately 65% of unobserved advertising journeys. The actual gain depends on the refusal rate, traffic volume, and the mode deployed (basic or advanced).
Consent Mode is the mechanism through which Google tags adapt their data collection to each visitor’s consent choice and compensate for cookie refusals through statistical conversion modeling. It has become essential for combining GDPR compliance with actionable advertising measurement in Europe.