searchDecoded Labs · Measurement explainer
GA4 consent mode simulator
See what happens to Analytics measurement when visitors don't consent to analytics cookies, and why a drop in observed traffic doesn't always mean fewer people visited.
The question
What can Analytics actually observe?
Your website can receive a visit even when Google Analytics 4 (GA4) can't observe it in the conventional cookie-based way. This simulator separates estimated website activity from the share that grants analytics consent.
It is a simplified educational model, not an audit of your consent banner or GA4 property. It can't calculate your true reporting difference or predict how much behavioural modelling may add.
Build a scenario
Follow the audience through measurement
Change the hypothetical traffic, consent rate and implementation. The audience remains the same. Only the way its activity can be measured changes.
Hypothetical website activity
100,000monthly visitsConventionally observable
70,000consented visitsPotential measurement gap
30,000visits without analytics storage100 representative signals
One dot represents 1% of the hypothetical audience
70 of 100 signals represent conventional measurement. The other 30 represent activity without analytics storage, for which measurements without cookies may be sent as potential modelling input.
Selected setup
Advanced Consent Mode
With analytics consent, GA4 can use analytics cookies for conventional measurement. Without consent, analytics cookies are not read or written, but measurements without cookies may still be sent.
These cookieless measurements can be an input to behavioural modelling only when Google determines that the property meets its eligibility and model-quality requirements. No recovery amount can be predicted here.
Consent-rate sensitivity
What a ten-point change would mean
The website activity stays fixed. This compares conventional observability at the current consent rate and ten percentage points either side.
- Conventionally observable
- 70,000
- Potential gap
- 30,000
- Conventionally observable
- 70,000
- Potential gap
- 30,000
- Conventionally observable
- 70,000
- Potential gap
- 30,000
Figures use the same monthly website activity as the active scenario. They do not predict a future consent rate.
Compare the setups
The consent gap stays the same, but the signal changes
All three examples respect the visitor's choice. The difference is whether Google tags remain blocked or adapt their behaviour after analytics storage is denied.
Tags blocked / no Consent Mode
Consent granted: Analytics measurement may be available.
Consent denied: Blocked analytics tags send no GA4 measurement from those visits.
Basic Consent Mode
Consent granted: Google tags load and conventional measurement is available.
Consent denied: Google tags stay blocked and no data is sent from the blocked tags.
Advanced Consent Mode
Consent granted: Analytics storage is granted and conventional measurement is available.
Consent denied: Analytics cookies aren't read or written. Measurements without cookies may be sent for basic measurement and modelling.
Understand the signals
What Consent Mode v2 actually controls
Consent Mode does not reduce every choice to one yes or no. Google tags receive a granted or denied state for separate purposes. Your consent banner or consent management platform is responsible for sending states that match the visitor's choices.
Keep the concepts separate
Behavioural modelling and key-event modelling answer different questions
Behavioural modelling
Estimates user and session behaviour that GA4 cannot directly observe when identifiers such as analytics cookies are unavailable. Google trains the model using observed data from the same property. It does not reconstruct individual visitors.
Key-event modelling
Estimates important actions that cannot be observed directly. A key event is an action marked as important in Analytics, such as a completed enquiry or purchase. This modelling supports reporting and attribution, but it is not the user-and-session estimate shown by behavioural modelling.
Behavioural modelling prerequisites
Check the published GA4 thresholds
Compare a property with Google's published prerequisites for behavioural modelling. Meeting every item does not guarantee that Google will activate modelling because separate model-quality requirements still apply.
Prerequisite check
Published prerequisites
- Advanced implementationGoogle tags load before the consent banner appears and continue loading when consent is denied.Not checked
- At least 1,000 denied events per dayEvents are sent with
analytics_storage='denied'.Not checked - Denied-event threshold for at least seven daysThe daily denied-event minimum is sustained rather than reached once.Not checked
- At least 1,000 consented users per dayDaily users send events with analytics storage granted.Not checked
- Consented-user threshold for seven of the previous 28 daysMore training time may still be needed after reaching this minimum.Not checked
This is a prerequisite check, not a prediction of eligibility, model activation or modelled traffic.
Method and limits
What the simulator calculates
The conventional estimate is monthly visits multiplied by the analytics consent rate. The potential measurement gap is the remaining share. Both figures are rounded to whole visits.
The calculation assumes the supplied consent rate applies evenly to the hypothetical audience. It doesn't account for repeat visitors, sessions, events, consent-banner behaviour, tag errors, regional rules, reporting identity or other causes of GA4 differences.
Advanced Consent Mode never adds a modelled number. The eligibility checker compares the selected implementation and supplied figures with Google's published minimum prerequisites. It cannot test Google's separate model-quality criteria or confirm that modelling will activate.
Technical descriptions checked against Google's Consent Mode overview, behavioural modelling requirements and key-event modelling guidance.