Why Your Meta Ads ROAS Is a Mathematical Lie
Profitability 2 min read

Why Your Meta Ads ROAS Is a Mathematical Lie

In 30 secondsYour Meta Ads account reports a ROAS of 6x, your Google Ads account reports 4x, and when you add up the attributed revenues it comes out to more than your store brought in for the month. It's not an error: that's how the system is designed. Meta attributes conversions by click (1-7 days) and by view (1 day by default); Google only by click. In sectors with a short purchase cycle (fashion, home, supplements), view attribution amplifies Meta's reported ROAS by between 30% and 60% over the real one. When a user sees a Meta ad, searches for the brand on Google and buys, both platforms count the sale and the revenue is counted twice. To deflate it, change the window to 7-day click + 1-day view, exclude view-through when measuring performance and always cross-reference with Shopify: the real combined ROAS is usually 50-70% of the reported sum.

Your Meta Ads account reports a ROAS of 6x. Your Google Ads account reports a ROAS of 4x. If you add both attributed revenues, you get more than your store brought in for the month.

It's not an error. That's how the system is designed. And until you correct it, scaling Meta Ads or Google Ads will cost you twice what you think.

Why Meta Ads inflates more than Google Ads

Meta attributes conversions by click (1-7 days) and by view (1 day by default). Google only by click. That means Meta can claim the sale of a user who saw a feed ad and bought two days later via organic. Google can't.

In sectors with a short purchase cycle (fashion, home, supplements), view attribution amplifies the reported ROAS by between 30% and 60% over the real ROAS.

The double count with Google Ads

The user sees a Meta ad. Three days later they search for your brand on Google and click on a Google Ads ad. They buy. Meta counts the sale (they saw the ad). Google also counts the sale (click + conversion).

If your reported Meta ROAS is 6x and Google's is 4x, part of that revenue is counted twice. When you cross-reference it with Shopify, the real combined ROAS is usually between 50% and 70% of the reported sum.

How to deflate Meta Ads

  • Change the attribution window to 7-day click + 1-day view (it's the closest to the real effect)
  • Exclude view-through when measuring performance, but use it to understand brand awareness
  • Always cross-reference with your revenue source (Shopify, ERP) — the platform can't be the referee

This doesn't mean Meta Ads doesn't work. It means the reported ROAS measures something different from what you manage. Once you have the real ROAS, budget decisions become predictable.

Sources

Frequently asked questions

Didn't the new iOS 14 attribution solve this?

iOS 14 limited view attribution on Apple devices, but the problem still exists on Android, web and other channels. The double attribution between Meta and Google remains.

Should I disable view-through in Meta Ads?

No, it's useful for measuring brand awareness. What you should do is not use it to optimize performance or to report ROAS to the finance team or management.

Which conversion window is the most realistic?

7-day click + 1-day view is the combination most aligned with real purchase behavior in ecommerce. With long cycles (electronics, travel), 28-day click still makes sense.