Ad Over-Claim Calculator
Run three platforms and they’ll claim roughly 130% of your real sales — each counts the same conversions. Enter what your platforms claim versus your actual orders to see your over-claim, and why to judge the mix on MER instead of summed ROAS.
Each ad platform attributes every conversion it can to itself, so the sum of platform-reported conversions exceeds your real orders. Over-claim = (platform-reported − actual) ÷ actual. The bigger it is, the more your channels are re-slicing one pie. Anchor on a single source of truth, judge the mix on MER (total revenue ÷ total spend), and use holdout tests to find what each channel truly causes.
Ad Over-Claim Calculator inputs and result
| Channels running | Typical claim ratio | Read |
|---|---|---|
| 1 | ~1.0× | Reconciles; last-touch usable |
| 2 | ~1.1–1.3× | Mild overlap |
| 3+ | ~1.3–1.6×+ | Heavy double-counting — use MER |
How to use this tool
- Add up what every platform claims.Sum the conversions Meta, TikTok, Google, and any other platform report for the same period.
- Enter your real conversions.Use one source of truth — GA4, your store, or your backend — for the identical period.
- Read the over-claim.The gap between claimed and real is how much your platforms are counting the same sales twice.
- Switch the scorecard to MER.When over-claim is high, judge the mix on marketing efficiency ratio — total revenue over total spend — not summed platform ROAS.
- Export and track it over time.Copy a share link, download the CSV, or print a PDF, and watch the ratio month to month.
RGM Expert Says
This is the number we put in front of clients who are “profitable on every platform” but somehow not growing. Each platform attributes the same sale to itself, so the silos all look like winners while the business is flat — the classic signature of double-counting. Quantifying it turns a vague suspicion into a board-ready figure.
We track the over-claim ratio as a standing KPI. When it climbs, it usually means budget is being shuffled between channels that fight over the same conversions rather than creating new demand — a signal to lean on blended ROAS / MER and to question the “scale the winner” reflex. A stable, low ratio means last-touch reads are roughly trustworthy; a high one means they are fiction.
The one thing this tool does not do is prove causation. Over-claim tells you the platforms are re-slicing one pie; it cannot tell you which channel actually grew the pie. For that you run a holdout or geo experiment. Use this to right-size your scorecard, then use incrementality to decide where the next dollar truly belongs.
How it works
Each ad platform claims every conversion it can attribute to itself, so when several run at once, the sum of their reported conversions exceeds your real total. Over-claim measures that gap:
The same idea as a multiplier is the claim ratio — how many times reality the platforms collectively claim:
The un-gameable alternative scorecard is marketing efficiency ratio, which uses totals that can’t be double-counted:
- Platform-reported — the sum of each channel’s self-attributed conversions.
- Actual — real conversions from one source of truth (GA4, orders).
- MER — business-level efficiency, immune to attribution overlap.
The over-claim and MER identities are standard in blended-measurement practice; for causal contribution, use a controlled experiment.
Every platform claims the same sale
A customer sees a Meta ad, clicks a Google search result, and buys after an email — and Meta, Google, and your email tool may each count that one sale. Sum their dashboards and you get more conversions than you actually had. The more channels you run, the wider the gap, which is why a multi-channel account can show glowing per-platform ROAS while blended performance is flat or sliding.
The fix is not to pick a “winner” among the platforms — that just rewards whichever one is best at claiming credit. It is to change the scorecard: anchor on one source of truth and judge the whole mix by MER, total revenue over total spend, which can’t be gamed by overlapping attribution. Reserve platform-reported numbers for in-channel optimization, where they’re still useful.
And remember the deeper limit: even reconciled, attributed conversions aren’t incrementality. Some of the “returned” revenue — especially on brand search and retargeting — would have happened anyway. Get the double-counting out of your scorecard with this tool, then prove which channels truly drive new demand with holdout or geo tests.
There is an organizational payoff too. When each channel owner is graded on their own platform’s reported ROAS, they are quietly incentivized to claim credit rather than grow the business — and they will, by leaning into retargeting and branded terms that harvest demand others created. Putting one blended number (MER) on the wall realigns everyone behind the same goal: total revenue per total dollar, not who won the attribution argument this week. The over-claim ratio is the fastest way to show a leadership team why that change of scorecard is overdue.
Over-claim reference
Orientation only; real ratios depend on your channels, attribution windows, and overlap.
| Situation | Typical claim ratio | What to do |
|---|---|---|
| Single channel | ~1.0× | Last-touch roughly usable |
| Two channels | ~1.1–1.3× | Watch the trend |
| Three or more | ~1.3–1.6×+ | Steer by MER; run holdouts |
What operators say
Summed platform ROAS over-counts because every channel claims the same conversions; MER — total revenue over total spend — is the un-gameable, business-level truth.