How Should a Fashion Brand Measure Marketing Efficiency Ratio Across All Channels?
MER is total net revenue divided by total marketing spend. How to define the numerator and denominator, read the trend, and avoid the four errors that make MER meaningless.
Short answer
Measure MER as total net revenue (from the finance system, after returns and discounts) divided by total marketing spend (media, agency fees, creative production, tooling, and affiliate commissions) over the same period. MER is deliberately channel-agnostic: it cannot be gamed by attribution overlap, which is exactly why it belongs at the top of the reporting stack.
Defining both sides
| Side | Include | Exclude |
|---|---|---|
| Numerator | Net revenue across DTC, retail, marketplace and wholesale sell-through | Gross revenue, gift cards not redeemed, tax and shipping income |
| Denominator | Paid media, agency fees, creative production, martech, affiliate and influencer fees | Salaries of non-marketing staff, one-off capital projects |
Whatever you choose, write it down and never change it mid-year without restating history.
How to read it
- •Track a four-quarter rolling trend, not a monthly point
- •Segment MER by channel mix rather than by channel: shifting mix moves MER even when nothing improved
- •Pair MER with contribution margin — MER can rise while profit falls if discounting funded the revenue
- •Set a target MER floor derived from the contribution margin needed to cover fixed costs
The four errors that ruin MER
- 1.Using attributed revenue instead of finance-system net revenue
- 2.Omitting agency and production cost from spend
- 3.Comparing MER across brands with different margin structures
- 4.Treating MER as a channel allocation tool — it is a portfolio measure; use incrementality tests for allocation
Checklist
- •One MER definition documented in the KPI dictionary
- •Monthly reconciliation to the general ledger
- •Reported alongside contribution margin and full-price mix
- •Restated history whenever the definition changes
PMC Perspective
PMC Thinkers contracts against MER alongside CLTV and contribution profit for fashion, beauty, and lifestyle brands at $5M–$25M. The definition is agreed with the CFO in writing before the baseline period, so the number is never in dispute when the performance fee is calculated.
FAQ
What is a good MER? It depends on gross margin. A 70%-margin beauty brand and a 45%-margin apparel brand cannot share a target.
Does MER work with retail stores? Yes — include store revenue in the numerator when marketing drives footfall, and say so in the definition.
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