In short. Consent choices can block analytics collection or remove persistent identifiers, while eligible Google Analytics properties can display modeled user activity.

Definition: Analytics consent gaps are differences between website activity and the activity observable in analytics because visitors decline consent for measurement. Depending on the implementation, consent choices can prevent data collection or remove the persistent identifiers used to connect events to users.

Key facts

As of 17 October 2026, Google's consent mode overview distinguishes basic mode, which blocks Google tags without consent, from advanced mode, which can send measurements without cookies.
Google's behavioral modeling documentation describes estimates for visitors who decline analytics cookies, based on similar visitors who accept them.
Google's website setup guide requires consent updates on the page where the choice occurs, before a page transition.
Google's Tag Assistant troubleshooting guide explains how to inspect default consent, subsequent updates and whether tags fire or are blocked.

Consent mode adjusts Google tag behavior to a visitor's consent state, meaning the granted or denied choice for each consent type. In Google's overview, analytics_storage controls storage related to analytics, including cookies used for measuring visit duration. With this type denied, the tag does not read or write first-party analytics cookies. Advanced mode can still transmit measurements; basic mode transfers no data when consent is declined.

The distinction affects counting. Google's behavioral modeling explanation gives the example of 10 page views: without a persistent identifier, Analytics cannot observe whether these belong to 10 users or 1 user. An event count therefore has a different meaning from a count of identifiable users or sessions.

For comparisons of AI referral traffic over time, these collection differences make consent configuration part of the measurement context.

When can modeled traffic appear in reports?

Behavioral modeling estimates user activity from observed data. Google's eligibility requirements include advanced consent mode across the site, at least 1,000 daily events with analytics_storage='denied' for at least 7 days, and at least 1,000 daily consenting users for 7 of the previous 28 days. Meeting these thresholds alone does not establish eligibility.

The Blended reporting identity displays modeled data when available. The data-quality icon indicates whether estimated user data is included. Comparing that status alongside traffic counts helps distinguish changes in reporting coverage from changes in visits.

How can a website check its implementation?

Google's setup instructions provide this default-denied example for gtag.js, the Google tag's JavaScript interface:

gtag('consent', 'default', {
  'ad_storage': 'denied',
  'ad_user_data': 'denied',
  'ad_personalization': 'denied',
  'analytics_storage': 'denied'
});

The default command belongs before commands that send measurement data. It is one part of an implementation: the consent solution must also update the state after a visitor's choice. The same guide warns that reloading a page after consent changes can lose original-page data, including a session_start event. Updates sent as a page unloads can also be canceled by the browser.

Google's troubleshooting procedure uses Tag Assistant's earliest Consent event to inspect defaults and the most recent Consent event to inspect updates. The Consent tab exposes the On-page Default and On-page Update columns. For Tag Manager implementations, the Tags tab shows which tags fired or were blocked. Where consent defaults vary by region, the procedure calls for repeating checks with different simulated geographic locations.

FAQ

Does declining analytics cookies stop every measurement request?

In Google's advanced consent mode, tags can send measurements without cookies when consent is denied. Basic mode blocks Google tags when consent is declined, so the implementation determines the collection gap.

Google's setup guide requires an update command after the visitor interacts with the consent solution. Consent mode itself does not save consent choices; the implementation must persist the choice and apply it on subsequent pages.

What should I inspect after changing the banner?

You can use Google's Tag Assistant checks to verify the default state before tags fire and the update after accepting or declining consent. Check each consent type configured by the banner, including analytics_storage.

Sources

Check how a page reads to answer engines. Open the GEO score analyzer

Key facts

How do consent choices change observed traffic?

When can modeled traffic appear in reports?

How can a website check its implementation?

Related terms

FAQ

Does declining analytics cookies stop every measurement request?

Is displaying a consent banner enough to update measurement?

What should I inspect after changing the banner?

Sources

Test a page and see what to fix first