How Much Money Are You Losing Without Correct Attribution?
Profitability 2 min read

How Much Money Are You Losing Without Correct Attribution?

In 30 secondsThe gap between your reported ROAS and your real ROAS has a concrete cost. If you invest €10,000/month in Google Ads with a reported ROAS of 4x, you assume €40,000 in monthly revenue. But if the real ROAS cross-referenced with the store is 2x, real revenue is €20,000: €20,000/month is fictional revenue on which you make real scaling decisions. The cascade effect is threefold: overinvestment in platforms with inflated attribution (Meta and Google at the same time), underinvestment in channels that aren't easily trackable (organic, email, direct), and margin decisions calculated with an incorrect CAC. In ecommerce with two or more active paid channels, the GAP between reported and real ROAS usually moves between 30% and 80%. Calculate it once: if it exceeds 30%, you've been making budget decisions for months on revenue that doesn't exist in your P&L.

If your reported ROAS is 4x and the real one is 2x, you're not measuring wrong. You're investing twice as much as necessary in scaling what already works.

The gap has a concrete cost that can be calculated in euros, not in gut feelings.

The formula for the cost of bad attribution

If you invest €10,000/month with a reported ROAS of 4x, you assume €40,000 in revenue. But the real ROAS is 2x: real revenue = €20,000. The difference, €20,000/month, is revenue that doesn't exist in your P&L.

  • Fictional revenue: reported ROAS × spend
  • Real revenue: ROAS cross-referenced with store × spend
  • Cost of bad attribution: fictional revenue − real revenue

The cost isn't theoretical. Every decision to raise or lower budget is made on the fictional revenue. If you scale up 30% based on an inflated ROAS, you're scaling a distortion.

The cascade effect

Poorly calibrated attribution pushes you toward three costly decisions: paying more for the account's acquisition, underbudgeting channels that do convert (organic, email), and reducing margin because the real costs per sale are higher than the reported ones.

  • Overinvestment in platforms with inflated attribution (Meta and Google Ads simultaneously)
  • Underinvestment in channels that aren't easily trackable (organic, email, direct)
  • Margin decisions calculated with an incorrect CAC

What to do

First, know the size of the problem. Calculate the GAP between your reported ROAS and the real one just once. If it exceeds 30%, there are decisions you've been making for months on distorted data.

Second is operational: connect each ads platform with your store and report both ROAS figures side by side. Unification doesn't solve attribution, but it makes it visible — and only what's visible gets managed.

Sources

Frequently asked questions

How big is the GAP between reported and real ROAS usually?

Between 30% and 80% in ecommerce businesses that invest in two or more paid channels at once. Below 15%, attribution is well calibrated.

Is the cost of bad attribution the same as the real loss?

No. The cost of bad attribution is the fictional revenue that doesn't exist. The real loss depends on the decisions made on that data. Bad attribution may cost you nothing if you never act on it, but most teams do act.

What tool should I use to unify attribution?

The minimum is a dashboard that cross-references ads with store data. The most complete option is probabilistic models like those in GA4 with consented data. To start, a sheet with spend per channel and revenue per channel cross-referenced with Shopify already brings the number to light.