A cookie banner records what a visitor agrees to. Consent mode is the layer that tells Google’s tags how to behave based on that choice. Together they change your analytics: visitors who decline are measured less, or not at all, depending on how you set things up. The goal is not to maximise tracking but to measure what you are entitled to measure and to understand the gaps.
What consent mode actually does
Consent mode lets Google tags adjust their behaviour to each visitor’s consent state. Google’s developer documentation lists four consent types (Google Tag Platform):
ad_storage: advertising cookies.analytics_storage: analytics cookies.ad_user_data: whether user data may be sent to Google for advertising.ad_personalization: whether personalised advertising is allowed.
The last two were added in consent mode v2. You set a default state on every page before any tags fire, then send an update when the visitor makes a choice. Google notes that consent mode does not save the choice itself, so your consent tool must store it and reapply it on later pages.
Basic versus advanced
Google Analytics help describes two implementation styles (Analytics Help).
| Basic | Advanced | |
|---|---|---|
| Google tags before consent | Blocked until the visitor agrees | Load, but with storage denied |
| Visitor declines | No data sent | Cookieless pings sent |
| Modelling of missing data | Not possible | Possible |
| Privacy posture | More conservative | Collects coarse signals even without consent |
With advanced mode, a declined visitor still produces a cookieless ping with limited data such as user agent and screen resolution. Analytics can use those pings for behavioural modelling to estimate what is missing. Google also says properties using the IAB TCF framework cannot model data for users who deny consent. Whether the advanced approach is appropriate for your organisation is a legal and policy decision, not only a technical one.
What to expect in your reports
- Lower observed numbers. Declined visitors drop out of user-level data in basic mode.
- Modelled figures in advanced mode. These are estimates, so label them as such when reporting.
- Broken attribution. Campaign comparisons across periods before and after a banner launch are not like for like.
- Differences between tools. Server logs, ad platforms and analytics will no longer agree, which is normal.
When you report to a board or client, state the consent rate and note when the banner went live. This connects to measuring creative campaign performance beyond views, where the lesson is to track outcomes you can defend rather than the largest number.
A setup checklist
- List every script that sets cookies or sends identifiers (analytics, ads, chat, embeds). Scripts also affect speed, as covered in Core Web Vitals for business.
- Choose a consent tool that supports consent mode and stores the visitor’s choice.
- Set defaults before any tag loads, and scope them to the regions where you show the banner, as Google recommends.
- Use
wait_for_updateif the consent tool loads asynchronously, so tags do not fire too early. - Send an update as soon as the visitor acts, before any page change.
- Test in a private window, with accept, reject and no choice.
- Document what you collect and why, and keep your privacy policy aligned.
Design the banner so it still converts
A banner is part of the first impression. Keep it short, make the choices equally easy, avoid blocking the content and test on small screens. A banner that covers the call to action hurts enquiries, which matters for what makes a business website convert.
The legal side, in brief
Privacy law differs by country. In Australia, the Privacy Act and the Australian Privacy Principles apply to many organisations, and the Office of the Australian Information Commissioner publishes guidance on tracking technologies. Businesses serving visitors in other regions may face additional rules. This article is general information, not legal advice; confirm your obligations with a qualified adviser before relying on any setup.
Limitations to accept
- Consent mode does not make a non-compliant setup compliant.
- Modelling is an estimate, not a record.
- Tools change; check Google’s current documentation when you configure.
Where Radiance Impact fits
Radiance Impact’s Technology team builds business websites and handles maintenance, including the tag and script decisions that sit behind a banner. If you want your analytics set up deliberately, see /technology or get in touch.
Sources
- Consent mode, Google Tag Platform
- About consent mode in Google Analytics, Analytics Help (Google)
