Definition
MER (also blended ROAS) divides all revenue by all marketing spend in a period. It sidesteps attribution arguments entirely: whatever the platforms claim, MER states what the whole machine produced. In a post-ATtribution world it is the north-star efficiency number.
Why it matters
Platform ROAS is an estimate; MER is arithmetic. We run accounts on MER with cohort checks beneath it.
Formula
Total revenue / Total ad spend
Benchmarks
3-5x healthy for D2C; track trend, not snapshot
All glossary terms