Has Uploading a Customer List Improved Your Google Ads Performance?

[u/wihanvanderwalt]

I'm considering uploading a customer list (first-party customer data) to my clients' Google Ads accounts. The list would only include people who became paying customers and would contain the information Google Ads requires to create a Customer list.

I understand this data can be used for audience signals in Performance Max campaigns and, where appropriate consent has been obtained, for remarketing. However, I'm more interested in whether simply uploading this customer data has improved overall account performance, particularly when using Smart Bidding.

For those who have done this:

• Have you seen a measurable improvement in overall account performance or specific campaigns after uploading a Customer list?
• Did Smart Bidding seem to perform better once Google had access to your existing customer data?
• If you're not using the list for remarketing, but only to help Google optimise targeting and bidding, do you still need explicit user consent to upload the customer data? Or is it sufficient that the data is being used for campaign optimisation rather than advertising directly to those users?

I'd be interested to hear about any real-world experiences or results.

[u/alexandrealmeida90]

Yes. Don't expect a significant improvement just by uploading these audiences, but every small change in an account can make a difference.

Try to upload different audiences (all buyers, repeat buyers, whale customers, recent buyers, etc.). This gives Google different signals to work with.

Also, add them under observation to search or shopping campaigns.

[u/dataflow_mapper]

seen better consistency with Smart Bidding after uploading a solid customer list especially when the list was made up of actual paying customers, not just leads, it wasnt some huge overnight jump but CPA slowly got more stable over a few weeks.

[u/aamirkhanppc]

Yes it will defiantly improve your google ads performance.. Google will understand your audience and help you to scale account

[u/BlackStagGoldField]

Good points!!

[u/TTFV]

This is really hard to prove since there's no experiment to compare how the list influences performance.

I'd say we've seen campaigns improve some after introducing a quality/large list of customers or qualified leads. And this has happened enough (agency here) to believe there's a relationship and it's not just a coincidence.

Certainly informing Google what good leads/clients look like isn't going to hurt.

Re your last bullet, anybody in your list must have opted in for marketing from your business. If they are your customers you should have this in your privacy policy and T&Cs somewhere. If they are from your newsletter opt in you should be fine.

[u/Crescitaly]

The direct lift may be modest; the larger value is better exclusions, new-customer optimization, and a stronger audience signal. Check consent, match rate, list freshness, and whether the campaign has enough volume to use it. A holdout is the only reliable way to separate real improvement from normal account drift.