How to verify a Google Ads agency's results (the real checklist)
Most agencies show a ROAS screenshot and call it proof. Here is the real checklist: account ownership, brand split, and matching Google's numbers to Shopify.
- 12,000+PMax campaigns audited
- 200+Live ecom clients
- €200M+Tracked sales
Ask any Google Ads agency how their clients are doing and you will hear a great number. 4x ROAS. 6x ROAS. Sometimes higher. Almost nobody checks if that number means what they think it means.
This is not an accusation against any specific agency. It is a structural problem. Google Ads reports on itself. The platform that shows you the results is the same platform selling you the clicks. Every agency, good or bad, is reporting numbers that came from a system with an incentive to look good. The honest ones build in checks. The rest just repeat what the dashboard says.
This is the checklist we use on our own accounts and the one we would want if we were hiring someone else. Six checks, no jargon, nothing that needs a data team to run.
Accounts we've reconciled
200+
Common Google vs Shopify gap
10-30%
Server-side tracking coverage
100%
Time to run the full checklist
~30 min
Check one: who owns the account
Start here, because this one decision decides how much leverage you have for every other check.
Some agencies build your Google Ads account inside their own manager account (called an MCC, short for My Client Center). That means the agency owns the account, not you. If you ever want to leave, you cannot just take the account with you. You start over: new account, no history, no audience data, and Google's algorithm re-learning your store from zero.
The fix is simple. You create the Google Ads account and the Merchant Center account under your own login. You grant the agency access to manage it. You can revoke that access any time, with everything - conversion history, audience lists, campaign structure - staying with you. This one setup decision is the difference between an agency that has to earn your business every month and one that can hold your data hostage on the way out.
Check two: split brand search from non-brand search
This is the single most common way agency results look better than they are, and it is completely legal - it is just not honest reporting.
Brand search is someone typing your store's name into Google, or a close variant of it. They already decided to buy from you before the ad even showed. It converts at a high rate no matter who is running the account, because the intent was already there. Non-brand search is someone typing a category or product term who has never heard of your store. That is the traffic an agency actually has to win.
Ask for a report that splits ROAS into brand campaigns and non-brand campaigns, shown separately. If most of the "great performance" is sitting in the brand line, the agency's real contribution is the non-brand number - and that is the one worth judging them on.
Check three: reconcile Google's numbers against your real sales
Google Ads reports its own conversions. Shopify (or your CRM) records what actually got paid for. These two numbers should be close. They are often not.
Pull the same date range from both systems. Compare total conversion value in Google Ads against actual net sales attributed to Google Ads traffic in Shopify. Some gap is normal - a few days of reporting lag, some cross-device purchases that are hard to stitch together. But a gap of 20% or more, especially one that stays wide month after month, means the tracking setup is broken or overcounting. And every bidding decision the agency makes is built on top of that broken number, which means every "optimization" might be optimizing toward something that never happened.
| Healthy account | Broken account | |
|---|---|---|
| Google vs Shopify gap | 0-10% | 20%+ and growing |
| Tracking method | Server-side + browser | Browser pixel only |
| Duplicate conversions | Checked monthly | Never checked |
| Reporting matches invoices | Yes, within days | No one has compared |
Check four: ask for incrementality, not just ROAS
Incrementality answers one question: would this sale have happened anyway, without the ad?
Last-click ROAS - the number almost every agency leads with - hands full credit to whatever the customer clicked on right before buying, even if they were already planning to buy. Retargeting is the classic case here. Ads shown to people who already visited your site or bought from you before will always look great, because those people were likely to convert anyway. An agency can lean hard into retargeting, report a blended ROAS across the whole account, and never separate out how much of that was new revenue versus revenue that would have shown up regardless.
A real incrementality test holds back the campaign for part of your audience or a region for a stretch of time and compares sales with the ads on versus off. It is not complicated to run. If an agency has never run one on your account, that is worth asking about directly - not as an accusation, just as a fair question about what the reported ROAS actually represents.
Check five: confirm tracking runs server-side
Browser-based tracking (a pixel that fires from the customer's device) has been losing accuracy for years. Ad blockers strip it. iOS privacy changes limit it. Cookie restrictions cut it further. Depending on the browser mix, a store relying only on browser pixels can be missing 20 to 40 percent of real conversions.
Server-side tracking sends the conversion event from your store's server directly to Google, bypassing the browser entirely. It is more accurate, harder to block, and it is the standard any agency working seriously in 2026 should already have installed. Ask directly: is my conversion tracking server-side, and can you show me it validated against my actual order data? A vague answer here usually means the answer is no.
Check six: watch for vanity ROAS on retargeting
This deserves its own line because it is so easy to miss inside a blended number.
If an agency reports one overall ROAS for the whole account, ask them to break it into prospecting (cold traffic that has never seen your brand) and retargeting (warm traffic that has). An account running 70% of budget into retargeting can post a beautiful blended ROAS while barely growing the customer base at all. That is not scaling - that is harvesting the same warm audience over and over. Growth comes from the prospecting number. That is the one to watch.
Their agency showed us 5.2x ROAS on the call. When we split it, prospecting was running at 1.8x and retargeting was carrying the blend at 11x on an audience of people who'd already bought twice. The store had not grown a single new customer segment in four months.
How ZenoX runs this on our own accounts
We are not writing this checklist as a sales pitch, but it would be dishonest to leave out how we handle it, since the honest answer is the whole point of the article.
Every ZenoX client owns their own Google Ads and Merchant Center account - we get manager access, never ownership. Every account gets server-side tracking installed and validated against Shopify data before we touch bids. Brand and non-brand are split by default in every report we send. We reconcile reported revenue with real store sales as a standard check, not a special request. That is what "transparency" should mean in practice, not just a word on a homepage.
If you want a second set of eyes on your own account, drop the store URL on WhatsApp and we will walk through these six checks live, on your real numbers - whether or not you ever become a client.
Frequently asked questions
How do I verify a Google Ads agency's results?
Check five things. One, you own the Google Ads and Merchant Center accounts, not the agency. Two, brand search is reported separately from non-brand search. Three, Google's reported conversions match your real Shopify sales within a small margin. Four, the agency can show incrementality, not just last-click ROAS. Five, tracking runs server-side, not only through a browser pixel that ad blockers and iOS strip out. Any agency doing honest work can walk you through all five in one call.
How do I know if my agency is taking credit for branded search?
Ask them to split the account report into brand and non-brand campaigns and show you the ROAS on each separately. Branded search - someone typing your store name into Google - converts at a high rate no matter who runs the account, because the person already decided to buy from you. That is not agency skill. If your reported ROAS is mostly branded clicks dressed up as "Google Ads performance," the agency is not doing much. Real skill shows up in the non-brand numbers - the clicks from people who did not know your store existed yet.
How do I check if Google's reported conversions match my real sales?
Pull two numbers for the same date range. Google Ads conversions and conversion value from the account. Actual net sales attributed to Google Ads traffic from Shopify or your CRM. They will never match exactly - some lag and some cross-device loss is normal. But if Google is reporting conversions 20% or more above what Shopify actually recorded, the tracking is broken or inflated, and every optimization built on top of it is optimizing toward a number that is not real.
What is incrementality and why does it matter for verifying an agency?
Incrementality means: would this sale have happened anyway, without the ad? Last-click ROAS credits the very last thing a customer clicked before buying, even if they were already coming back to buy. Retargeting ads are the classic case - they often show a huge ROAS because they get shown to people who were already going to re-purchase. A real incrementality check runs a geo or audience holdout test and compares sales with the campaign on versus off. If an agency has never run one, ask why.
Can an agency inflate ROAS with retargeting alone?
Yes, and it is one of the oldest tricks in paid media. Retargeting ads are shown to people who already visited your site or bought before, so they convert at a high rate almost regardless of the ad itself. An agency can pour a disproportionate share of budget into retargeting, report a blended ROAS that looks excellent, and never mention that most of those buyers would have come back anyway. Ask for the ROAS split by campaign type - prospecting versus retargeting - not just the blended number.
Should I own my own Google Ads and Merchant Center account?
Yes, always. If the agency owns the account under their own manager account (MCC) and you leave, you can lose the account history, conversion data, and audience lists built up over months or years - and have to start the learning phase over with a new agency. When you own the account and grant the agency access instead, you keep everything on exit and switching agencies costs you nothing but a short handover.