Advertising dashboards are full of numbers, and each platform reports its own version of success. Small cross-border stores often make decisions based on the wrong metric, scaling campaigns that look profitable in one dashboard while the business as a whole loses money. Three metrics, used together, give a clearer picture.
ROAS: return on ad spend
ROAS equals revenue attributed to ads divided by ad spend. A ROAS of 3 means three units of revenue for every unit spent.
Strengths: easy to understand, available in every ad platform. Weaknesses: it uses revenue, not profit, and it depends on each platform's attribution. Two platforms may both claim credit for the same order, so adding their ROAS figures overstates results.
CPA: cost per acquisition
CPA equals ad spend divided by the number of conversions, usually purchases.
Strengths: easy to compare with your margin per order. If your gross profit per order is 20 and your CPA is 25, you lose money on each first order. Weaknesses: like ROAS, it depends on attribution, and it treats all orders as equal regardless of value.
MER: marketing efficiency ratio
MER equals total store revenue divided by total marketing spend across all channels, over the same period.
Strengths: it does not depend on any platform's attribution, so it reflects reality at the business level. If you increase ad spend and MER falls sharply, the extra spend is not paying off. Weaknesses: it does not tell you which channel or campaign is working.
Using them together
- Use platform ROAS and CPA to compare campaigns, ads and audiences within a platform.
- Use MER weekly to check whether total marketing is profitable.
- Calculate your break-even ROAS and maximum CPA from your margin. For example, if your gross margin is 40 percent, break-even ROAS is 2.5 before other costs.
Add profit to the picture
Revenue metrics ignore returns, discounts, shipping and payment fees. Once a month, calculate contribution margin after ad spend: revenue minus product cost, shipping, fees, returns and marketing. That number decides whether you can scale.
Common mistakes
- Judging campaigns too early, before enough conversions.
- Comparing ROAS across platforms with different attribution windows.
- Ignoring repeat purchases, which can make a high CPA acceptable.
Analytics and profit calculator tools are listed in the Facebook520 tool directory, and terms such as attribution window and contribution margin are explained in the Facebook520 cross-border encyclopedia.
Published by Facebook520 Cross-Border Navigation.