ROAS — revenue divided by ad spend — is the headline metric for e-commerce ads. On its own it can push you toward the wrong decisions.
011. ROAS, with context
A high ROAS on a tiny budget may not hold as you scale. A lower ROAS on new customers can be worth more than a high one on people who would have bought anyway. Look at it by campaign and by audience, not as one account-wide number.
022. Cost per new customer
Growth comes from new buyers. Knowing what each new customer costs — and comparing it to what they spend over time — tells you how much you can afford to pay for them.
033. Contribution after ad spend
Revenue minus product cost, delivery and ad spend. This is what the business actually keeps, and it's the number that decides whether to scale.
A good week in the ads account should also be a good week in the bank account.