Incrementality Testing: Which Orders Are Truly New?

Public core framework

• Turn the question into plain language: would orders, new customers, and contribution profit fall without this ad layer? Before reading platform ROAS, name the layer being tested: branded search, remarketing, PMax, audience, or region.
• Check order volume, whether regions or audiences can be separated, whether promos, stock, and email cadence are stable, whether the buying cycle is covered, whether tracking is stable, and whether a 10-14 day test is safe enough.
• Compare platform revenue with Shopify total orders, new customers, non-paid orders, AOV, refunds, checkout completion, and contribution profit. If platform revenue falls but total orders and profit hold, the layer may be capturing existing demand.