Cookies: the impact of GDPR compliance on audience tracking

Lucas Perrosé . March 29, 2021

As of April 1, 2021, all websites will have to offer cookie management that complies with the requirements of the GDPR and the ePrivacy Directive, according to the guidelines established by the CNIL (Commission Nationale de l’Informatique et des Libertés). This deadline implies a major change in the way audience data will be collected and analyzed.

The principles of cookie management confirmed by the CNIL

The goal of the new cookie management rules is to give users more control over how their data is used for advertising and/or analytics purposes. These principles, adopted in September 2020 (access the deliberation), will therefore come into force on March 31, 2021 and will reinforce the central notion of user consent.

The main principles dictated by the CNIL :

  • continuing to browse a site no longer constitutes proof of the Internet user’s consent
  • consent must be given by a clear positive act (clicking on “I accept” in a cookie banner)
  • refusing the use of cookies must be as simple as accepting for the user
  • the user must be able to withdraw his consent at any time and easily

What impact does this have on audience data?

This new cookie collection system will mechanically disrupt the audience statistics of a website (traffic by channel, conversion, bounce rate, pages/session,…). As tracking is only triggered when the user accepts it, a part of the audience will no longer be tracked: you can expect to lose between 50 and 70% of the data, depending on the sector and the cookie banner used.

The integration of the CNIL principles will therefore impact the reading of acquisition statistics in the conduct of SEO, PPC or Social Ads strategies. The evolutions in terms of results in the coming weeks will have to be nuanced, and comparisons with a previous period may be complicated depending on the KPIs.

How to adapt your tracking and monitoring?

As Google is not one of the solutions exempted from the collection of consent (since cookies are used for advertising), platforms such as Google Analytics or Google Ads will be directly impacted by this change and therefore show a loss of data. The deployment of Google Analytics 4 directly echoes these RGPD requirements, as Google plans to close the gap in data collection thanks to machine learning, the reliability of which has not yet been proven.

It is then possible to set up complementary audience tracking solutions authorized by the CNIL to collect cookies without consent, like Matomo. They can allow a continuity in the information feedback, and measure the part of the users not activating the cookies, in order to estimate the losses on Analytics or Google Ads.

Website-specific data, such as online revenue, can also be used to estimate the amount of data lost in the migration.

The traffic data available in Google Search Console will not be impacted (clicks are collected from Google results pages, and not on the sites). Mainly used in SEO, they can be used again in SEA to compare some gaps.

Finally, optimizing the cookie acceptance pop-in (readability, speech, layout,…) can increase the consent share up to 75%, thus minimizing data loss.