Metrico glossary
Marketing Efficiency Ratio (MER)
MER is a blended efficiency ratio commonly used to compare store revenue with total included marketing or paid-media spend.
Definition
Ecommerce teams often use MER as a business-level efficiency view rather than a channel-attribution metric. Definitions vary: one team may divide total Shopify revenue by paid-media spend, while another includes broader marketing costs. The formula should therefore be stated explicitly wherever MER is displayed.
Formula
Common ecommerce MER = total store revenue ÷ total included paid-media spend
Example
$100,000 of store revenue ÷ $25,000 of included paid-media spend = 4.0 MER.
What to remember
- MER does not prove that advertising caused all store revenue.
- An incomplete spend denominator can make MER look artificially strong.
- Use lower-level channel and campaign metrics to explain why MER changed.