First-party data and enhanced conversions: recovering the missing conversions
Your own customer data is the only category that reliably grows. Enhanced conversions, offline imports and a CRM connection return part of what cookies lost — and Google reports single-digit percentage gains in incremental return for it.
- Enhanced conversions send a hashed email or phone and match conversions that would otherwise be missing.
- For advertisers with enhanced conversions and value bidding, Google reported 8 % incremental ROAS across 99 lift studies.
- In lead generation the biggest gain is not technology but feeding closed deals from the CRM back into the ad system.
For a decade all measurement in digital advertising rested on third-party cookies. They are effectively finished, and what remained is being trimmed by consent. The answer from platforms and advertisers alike is the same: first-party data, the information a customer gave you directly.
This article is about what to do with it in practice — from the simplest step to the one that changes the whole economics of an enquiry-driven account.
Enhanced conversions: the first step
The principle: at the moment of conversion you send, alongside the event, a hashed customer identifier — most often an email, sometimes a phone number or address. Google compares it with its signed-in users and can attribute conversions that would otherwise be lost (a different device, a missing cookie, consent denied on the click-tracking side).
Two variants:
- Enhanced conversions for web. They match a conversion to the original click. Deployed via the tracking code, Tag Manager or server-side.
- Enhanced conversions for leads. You send Google what later happened to the enquiry — that it became a deal, and for how much. This is the crucial step for services.
The condition is consent to sending user data for advertising (ad_user_data). Without it nothing is sent. See Consent Mode v2.
What measurement says it delivers
The strongest available figure: Google reports 8 % incremental ROAS on Search campaigns for advertisers who bid to conversion value and have enhanced conversions in place. It comes from an analysis of 99 conversion lift studies run globally between April 2024 and April 2025. That is a result from controlled lift studies rather than a before-and-after comparison — and against most numbers in this field, that is a large difference.
Further figures Google published around the September 2026 measurement update:
- An average 14 % uplift in conversions for advertisers using the Google tag gateway.
- Over 20 % for Demand Gen campaigns.
- An average 26 % increase in incremental ROAS when offline and app data is connected through Data Manager.
- For enhanced conversions in GA4 and DV360, an average 11 % more conversions in Search.
All come from Google and some we found only second-hand on agency blogs rather than in the primary announcement. They are also averages across very different accounts and they measure different things: “more conversions” means more measured conversions, which is not the same as more sales. The only figure in the list that genuinely measures additional business is the 8 % incremental ROAS from the lift studies.
Offline conversions: the biggest change in lead generation
This is the part we recommend above anything else in this article. In enquiry-driven businesses not all enquiries are worth the same — some become a half-million deal, others were a mistake. The ad system knows none of that and optimises for the number of forms.
Send back “this enquiry became a deal worth X” and its behaviour changes fundamentally: it starts looking for people similar to those who buy, not those who fill in forms.
How to do it:
- On form submission, store the click identifier (GCLID) or a hashed email in the CRM.
- When a salesperson closes a deal, upload an offline conversion to Google Ads with the GCLID, date and value.
- Upload intermediate stages too (qualified enquiry, meeting, quote) if closed deals alone are too few to learn from.
- Set the bidding strategy to value, not count.
Technically it is a few days of work. Commercially it is the highest-return thing you can do in an enquiry-driven account. Detail in B2B PPC: generating leads sales will actually take.
Customer lists
Uploading a customer list (hashed) opens up three things:
- Excluding existing customers from acquisition campaigns. For subscriptions and services that is an immediate saving.
- Similar audiences built on actual customers rather than visitors.
- A new-customer goal in Performance Max — the system then knows who counts as new.
Mind the legal side: uploading customer data into an advertising platform is processing of personal data and requires a legal basis and informing the people concerned. It is not a technical detail.
Server-side tracking
The last layer, worth it on larger accounts. Data is sent from your own server rather than the browser. The benefits:
- Resistance to blockers and to browser cookie restrictions.
- Control over what is sent — you can strip or omit fields.
- A faster site, because fewer scripts run in the browser.
The price: a more complex deployment, running a container, and a greater need for someone who understands it. For a small site it is unnecessary; for a shop with tens of thousands of orders usually not.
The order to deploy in
- Correct Consent Mode in advanced mode. Without it the rest is pointless.
- Enhanced conversions for web. The best ratio of effort to benefit.
- One main conversion with a truthful value (excluding VAT and shipping, after returns).
- Offline conversions from the CRM — in enquiry-driven firms this outranks everything else.
- Customer lists for exclusion and for defining a new customer.
- Server-side tracking, if you have both the volume and the capacity.
What to take away
First-party data is not a buzzword but the only category of data that will not vanish from under you. What matters most is not the technology but the connection: getting information into the ad system about what happened to a conversion afterwards. A company that can say “this enquiry produced a deal worth €16,000” has an advantage in the account that no amount of bid optimisation will close.
Common questions
What are enhanced conversions?
A Google Ads feature that sends a hashed customer identifier, most often an email or phone number, alongside the conversion event. Google compares it with its signed-in users and can therefore attribute conversions that would otherwise be lost — for example a purchase completed on another device or a case where the cookie is missing. The condition is consent to sending user data for advertising; without it nothing is sent.
How much do enhanced conversions actually deliver?
The strongest available figure comes from Google: 8 per cent incremental return on Search campaigns for advertisers who bid to conversion value and have enhanced conversions deployed. It is based on an analysis of 99 conversion lift studies run globally between April 2024 and April 2025. Other frequently quoted numbers, such as fourteen per cent more conversions with the Google tag gateway, measure only more measured conversions rather than more actual sales — a material difference.
How do I upload offline conversions from a CRM to Google Ads?
On form submission, store the GCLID click identifier or a hashed email in the CRM. When a salesperson closes the deal, upload an offline conversion back to Google Ads with that identifier, the date and the deal value. If closed deals are too few for the strategy to learn from, upload intermediate stages too, such as a qualified enquiry or a meeting. Then switch the bidding strategy to optimise for value rather than conversion count.
- Benefits of Enhanced Conversions in Google Ads, Workshop DigitalSecond-hand source for the 8 % incremental ROAS from 99 conversion lift studies (April 2024 to April 2025). The original measurement comes from Google; we did not verify the primary document.
- Google Ads Data Strength Uplift Metric: The September 2026 Measurement Update Explained, MiraflowSource of the figures on 14 % more conversions with the Google tag gateway, over 20 % for Demand Gen and a 26 % rise in incremental ROAS via Data Manager. All originate from Google and are cited here second-hand.
- Google Ads September 2026: New Data Strength Tools Give Ecommerce Brands an Edge, Common Thread CollectiveDescription of the September 2026 measurement update and the Data Strength Uplift metric. An agency source.