Why your ads should be measured against profit, not ROAS

Return on ad spend (ROAS) is the number every ads dashboard puts first. It is useful, but it only tells you how much revenue came back for each pound spent. It says nothing about what that revenue cost you to deliver, whether the customer would have bought anyway, or whether they will ever come back.

Brands that judge campaigns by ROAS alone often cut the campaigns that are growing the business and scale the ones that aren't.

Start with your break-even ROAS

Every product has a ROAS below which advertising loses money. To find it, take your margin after the cost of goods, delivery, payment fees and returns, as a share of the selling price. Break-even ROAS is one divided by that margin.

For example, if you keep 40% of the selling price after those costs, your break-even ROAS is 2.5. A campaign at 3 makes a little money on the first order; a campaign at 2 loses some. Two brands with the same ROAS can be in very different positions.

Measure contribution, not revenue

Contribution is what is left after the cost of the product, fulfilment and the advertising itself. It is the money that pays for your team, your rent and your growth. Reporting contribution per campaign, even roughly, changes the conversation from "which campaign has the best ROAS?" to "which campaign adds the most profit?"

A campaign with a lower ROAS but much larger volume can add more contribution than a small campaign with an impressive ratio.

Separate new customers from returning ones

Branded search and retargeting usually show the highest ROAS because they reach people who already know you. Many of those people would have bought anyway. Prospecting campaigns on Meta, YouTube or non-branded search show lower ROAS because they introduce you to new people, and that is where growth comes from.

• Track new-customer revenue separately where the platform allows it.
• Give prospecting a target based on the value of a customer over time, not just the first order.
• Keep branded and retargeting campaigns lean, and check how much they really add.

Test whether ads cause the sales

Platforms take credit generously. The most reliable way to see what a channel really adds is to test it: pause a campaign in one region or for a set period and compare sales against a similar region or period where it kept running. Google and Meta both offer lift studies for larger budgets. Even a simple test once a quarter will tell you more than any attribution model.

Report one number the whole business understands

We build reports around one headline figure: marketing efficiency ratio (MER), which is total revenue divided by total ad spend across every channel. Alongside it we show contribution profit and new customers. Platform ROAS is still there, as a tool for optimising inside each channel, but it no longer decides the budget on its own.

What to do this month

1. Work out break-even ROAS for your main product groups.
2. Split your reporting into new and returning customers.
3. Pick one campaign whose value you doubt and design a simple test.

If you would like your Google, Meta or TikTok ads judged against profit, our performance marketing team can set up the reporting and the tests with you.