Consent Mode
Short definition
Consent Mode is a setup that adjusts how Google tags collect data based on a visitor's cookie choice.
When a visitor declines cookies, Google Analytics and Google Ads tags stop collecting personal data and instead build a statistical model from anonymised signals. Totals are not lost entirely, but no individual is tracked. That modelling draws on the past behaviour of similar visitors, so it only ever partly replaces a real measurement.
Privacy rules in the EU and the UK restrict collecting personal data without consent; Consent Mode is an attempt to balance that requirement against advertising measurement. Its second version collects more detailed consent signals. Whether a setup is working correctly can be checked by inspecting tag requests in a browser's developer tools.
Without Consent Mode set up, or set up incompletely, data for visitors who decline consent is not modelled at all, which makes conversion numbers look lower than they really are.
Why it matters
Without Consent Mode, privacy compliance and advertising measurement pull against each other: either data is collected against the rules, or measurement falls badly short. Set up correctly, it balances both requirements without leaving the business exposed to legal or reputational risk.
