What is the most common mistake comparing ROAS across platforms?

Comparing platforms set to different attribution windows or different timezones, which manufactures a gap that is not real. Align the date range and the timezone first, and write down which attribution window each platform was using.

What does a claim ratio above one mean?

That your ad platforms collectively claim more revenue than your store actually took, because each counts conversions it touched and touches overlap. It is expected. The useful information is the size of the excess and which channels contribute most of it.

Should I reallocate budget after a one-hour comparison?

Not on that alone. Use it to identify the channel where the gap is largest and the budget biggest, then run a proper holdout on that one. The comparison is triage that tells you where to spend your expensive instrument.

Compare platform and causal ROAS in one hour

Three data pulls and one table turn a vague suspicion that reported ROAS is inflated into a per-channel number. Here is the hour, step by step.

Three platforms, three answers, one budget to defend. Your GA4 export already holds the answer, and the first finding is free and never leaves your browser. Get your first finding free

By Joris van Huët, Founder & CEOUpdated 2026-10-063 min read

Run the numbers for your store: the free ad platform over-reporting checker.

One hour, three pulls and a single table converts "I think our reported ROAS is inflated" into a per-channel number you can put on a slide. No modelling is required for the first two thirds of it.

The hour

Minutes	What you pull	Where from
0 to 10	Actual revenue for the window	Your store admin
10 to 30	Claimed revenue and spend, per platform	Each ad platform, same window, same timezone
30 to 40	Build the table and compute the ratio	A spreadsheet
40 to 60	Causal estimate per channel	An analytics export and a read

Watch the window and the timezone

The most common error is comparing platforms on different attribution windows or different timezones, which manufactures a gap that is not real. Set every platform to the same date range, note which attribution window each one is using, and write it down, because you will not remember next quarter.

Build the table

Five columns: channel, spend, platform-claimed revenue, reported ROAS, and share of total claimed. Then one line at the bottom: total claimed revenue against actual revenue, and the ratio between them.

A ratio above one is expected. What matters is the size, and which channels contribute most to the excess. That is usually visible immediately and it is often the most useful twenty minutes anyone on the team spends that quarter. The walkthrough is in the one-hour ROAS audit.

Add the causal column

Put that column beside the reported one. The two are not the same number and are not meant to converge; the point is the pattern of the difference.

What to do next

Do not reallocate on the strength of one hour. Use the table to choose the single channel where the gap is largest and the budget is biggest, and run a geo holdout on that one. The hour is triage; the holdout is the verdict.

The one habit worth keeping

Run the same table quarterly with the same definitions. The level is interesting once; the trend is useful forever, particularly when a platform changes its default attribution window and your gap moves without anything in your account changing.

Frequently asked questions

What is the most common mistake comparing ROAS across platforms?
Comparing platforms set to different attribution windows or different timezones, which manufactures a gap that is not real. Align the date range and the timezone first, and write down which attribution window each platform was using.
What does a claim ratio above one mean?
That your ad platforms collectively claim more revenue than your store actually took, because each counts conversions it touched and touches overlap. It is expected. The useful information is the size of the excess and which channels contribute most of it.
Should I reallocate budget after a one-hour comparison?
Not on that alone. Use it to identify the channel where the gap is largest and the budget biggest, then run a proper holdout on that one. The comparison is triage that tells you where to spend your expensive instrument.

Go deeper: Causal attribution, explained.

Sixty-second versions of these ideas: Causality Engine on YouTube Shorts.

Have an audience of ecommerce operators? Earn 20% recurring commission by recommending the €99 read.

Keep reading

Terms in this article

Browse the full glossary