How MER actually works
MER is deliberately dumb, and that is its strength. You take every dollar of revenue the business booked in a period and divide it by every dollar spent on marketing in that same period. No pixels, no attribution windows, no view-through credit. Because it never asks which channel drove which sale, it cannot be fooled by the double-counting that inflates platform ROAS. If Google, Meta, and your email tool all claim the same purchase, blended MER still only counts that purchase once.
MER vs ROAS: the CFO metric vs the channel metric
ROAS answers a channel question: is Google Ads pulling its weight. MER answers a business question: is the whole marketing engine profitable. A brand can post a 5.0 ROAS on the Google Ads dashboard while its MER sits at 2.1, because the platform is claiming credit for organic and returning-customer revenue it did not create. When those two numbers drift apart, the platform is over-reporting. iClick treats a widening ROAS to MER gap as the single clearest sign that budget is being wasted on demand that already existed.
What counts as a healthy MER
There is no universal target. Healthy MER is a function of gross margin and how much of the business is repeat revenue. A subscription brand with high lifetime value can run a MER near break-even on first order and still be wildly profitable. A one-time-purchase product at 30 percent margin needs a MER above roughly 3.3 just to cover the cost of goods. The right way to set the number is to work back from contribution margin, not to copy a competitor's benchmark.
When to steer by MER instead of ROAS
The more channels you run, the more attribution lies to you, and the more you should trust MER. On accounts spending above 100,000 dollars a month across Google, Meta, and marketplaces, iClick sets the MER target first, then allocates channel ROAS budgets underneath it. On a single-channel account, ROAS and MER converge and either works. The failure mode is optimising each channel to a great ROAS in isolation while the blended number quietly falls, which is what happens when every platform is paid to take credit for the same customer.
