Why reported ROAS overstates returns
Dashboards credit would-have-happened-anyway conversions, double-count across platforms, and lean on tracking that privacy changes have degraded. The result reliably flatters paid channels, especially retargeting and branded demand.
How to measure true ROAS
Estimate each channel's incremental contribution causally and divide by spend. That gives true (incremental) ROAS: the return on sales the channel caused. No pixel required - your Shopify + GA4 history is enough to estimate what each channel caused.
Frequently asked questions
Is true ROAS the same as incremental ROAS?
Yes - both mean return on caused sales, not credited sales.Why is mine lower than the dashboard?
Because the dashboard counts non-incremental conversions.
The pillar this guide links up to: Causal Attribution