According to the Google Ads Help, consent is denied by default unless configured otherwise. After a cookie banner goes live, part of the conversions is therefore missing by design. The default consent state, however, is set by the website or the cookie banner. When a specific choice is missing, the system assumes, according to the Help, that consent is granted. More conversions can go missing because of settings in Google Tag Manager (GTM from here on).
Orders keep coming in the store's admin, but you see fewer of them in GA4 or Google Ads. GA4 now calls conversions key events.
You can fix a settings error in GTM yourself. I will describe the consent settings and how to verify them in Tag Assistant.
Why conversions go missing after a cookie banner goes live
Conversions go missing for two reasons: partly because the visitor did not give consent, partly because of the settings in GTM.
In the basic version of Consent Mode, Google tags do not load until the visitor responds to the banner. In the advanced version they load when the website opens and, on denial, send information about the consent state and cookieless pings. According to the Help, the system assumes consent is granted when neither the website nor the cookie banner sets a default consent state. Expect a large share of visits to stay without consent even with the correct setup.
A gap from the settings can be caused, for example, by the Require additional consent for tag to fire option. When taking over accounts, I went through 14 GTM containers with 225 tags. In 11 of the 14 containers, no tag had this option. On one container, however, 7 GA4 tags waited for additional consent, including the tag measuring leads, and the default consent state was missing: leads from people without consent were lost completely.
Diagram
A visitor declines consent. What does the tag do?
Built-in consent checks (advanced version)
- The tag loads when the website opens
- On denial it stores no cookie
- The consent state and cookieless pings go out
Require additional consent for tag to fire
- The tag waits until all the specified consent types have the status granted
- Without consent it does not fire and the data is lost completely
On one website the cause lay outside GTM: a security header blocked GA4, Google Ads and the cookie banner, and consent was recorded without the banner ever showing (760 clicks, 1 conversion, −99% visits in GA4).
Modeling can fill in part of the gap, but only above its threshold. According to the Google Ads Help, users who consent convert two to five times more often than those who do not, so the drop in conversions can be smaller than the share of denials. An example from the Help: a 50% consent rate, a conversion drop of only 19%.
GA4 models both behavior and conversions, that is, key events. The condition for behavioral modeling in GA4 is different from the one for conversion modeling in Google Ads:
| modeling according to the Help | tool | condition according to the Help |
|---|---|---|
| behavioral modeling | GA4 | at least 1,000 events with analytics_storage='denied' per day for at least 7 days and at least 1,000 users with analytics_storage='granted' per day for at least 7 of the previous 28 days |
| conversion modeling | Google Ads | at least 700 ad clicks over 7 days per country and domain grouping |
Google Ads shows modeled conversions in the Conversions column. In GA4 you see modeled data with the Blended reporting identity.
Consent Settings in Google Tag Manager have two parts
In any web tag, open Advanced Settings > Consent Settings. The first part consists of the built-in consent checks. They change the tag's behavior based on the consent state.
The second part is Additional Consent Checks. When you choose Require additional consent for tag to fire on a tag, a + Add required consent button appears. The tag then fires only when all the specified consent types have the status granted.
How to set up Consent Mode in GTM and verify it
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Default consent state. Fire the consent management platform tag or the tag for default consent settings on the Consent Initialization - All Pages trigger. Every web container has that trigger by default, and it always fires before other tags. Tag Manager has templates for selected CMP platforms.
When taking over accounts, the consent check failed on 7 of 16 websites. 3 websites sent neither the default state nor the consent update: the banner only blocked scripts, or Consent Mode was missing entirely. On 3 websites the banner sent only the update without a default state. One website set only
analytics_storagein the default state, and nobody set thead_*signals. -
Google tags without Additional Consent Checks. On the Google tag, open Tag Configuration > Advanced Settings > Consent Settings and in Additional Consent Checks select Not set or No additional consent required. Then preview and publish the container. On the container with the lost leads, checking the draft version of the container did not show the error: only the live website showed it, and publishing a new container version fixed it.
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Verification. Start Tag Assistant and select the first Consent event in the Summary section. On the Consent tab, the On-page Default column should show Denied. After accepting the banner, select the latest Consent event: the On-page Update column should show Granted. In Google Ads, the status appears on the conversion action's Diagnostics tab, which can take up to 48 hours. In GA4, open Admin > Data collection and modification > Consent settings, where the notice update for the data stream can take 48 to 72 hours. In Google Ads, the impact of modeling shows up seven days after implementation, if the domain and country pair meets the volume requirements. The increase in modeled conversions then shows over four weeks.
Repeat the verification after launching a new website. On one website, the switch to a new site lost the Consent Mode that the old site had working correctly. 11 tags fired there before consent. The Google Ads visitor list had 8 people and the GA4 lists 0, with 263 visits from paid search.
Timeline
When you see the result of the verification
Up to 48 hours
Consent status in Google Ads
The conversion action's Diagnostics tab.48 to 72 hours
Notice update in GA4
Consent settings for the data stream.7 days after implementation
Impact of modeling in Google Ads
When the domain and country pair meets the volume requirements.The next four weeks
Increase in modeled conversions
The increase shows over four weeks.
Consent signals and what denying them limits
There are four consent types:
| consent type | what it controls according to the Help | what denial limits |
|---|---|---|
ad_storage | storage of information related to advertising, such as cookies | no new advertising cookies can be written |
analytics_storage | storage of information related to analytics, such as visit duration | first-party analytics cookies cannot be read or written, Google Analytics receives cookieless pings |
ad_user_data | consent to sending user data related to Google advertising | limited export of conversion data tied to click IDs to Google Ads |
ad_personalization | consent to personalized advertising | personalized advertising off, no data for remarketing in Google Ads, Display & Video 360 and Search Ads 360 |
Personalized advertising needs consent for both types, ad_user_data and ad_personalization.
Go over the consent state with your PPC provider too. I wrote down what to ask a provider before you sign.
Measurement, including the consent state, is part of what Google Ads management includes in its price.
Summary
- The conversion gap after a banner goes live has two causes: denied consent and errors in the GTM settings.
- The Require additional consent for tag to fire option does not fire the tag without granted consent. Do not combine it with Consent Mode on Google tags.
- Put the tag with the default consent state on the Consent Initialization - All Pages trigger.
- The check result does not show up everywhere at once: Tag Assistant shows the state on the Consent events. In Google Ads, the status can take up to 48 hours to show, in some cases up to two weeks. In GA4, count on 48 to 72 hours.
- Google Ads models conversions only from 700 ad clicks, counted over 7 days separately for each country and domain.
- Denied
ad_user_dataandad_personalizationlimit the export of conversions by click ID and switch off personalized advertising, remarketing included.
In the container, open the Google tag, the GA4 tag and the Google Ads conversion tags, and go through Consent Settings on all three. Verify the result in Tag Assistant and then on the conversion action's Diagnostics tab in Google Ads. You may wait up to 48 hours for the status there, in exceptional cases up to two weeks.
