MER (Marketing Efficiency Ratio)

Definition

MER (also called blended ROAS) is total revenue divided by total marketing spend over the same period. It's useful for top-down health checks.

Formula

MER = total revenue / total marketing spend

Example

If total revenue is $500k and total marketing spend is $100k, MER = $500k / $100k = 5.0.

Common mistakes

• Using MER alone to optimize channel budgets (it hides what's working).
• Not adjusting for seasonality, promos, and pricing changes.

Why this matters

This term matters because it affects how you interpret performance and make budget decisions. If you use inconsistent definitions or windows, ROAS/CPA can look "better" while profit gets worse.

Practical checklist

• Write a 1-line definition for "MER (Marketing Efficiency Ratio)" that your team will use consistently.
• Keep the time window consistent (weekly/monthly/quarterly) when comparing trends.
• Segment results (channel/plan/cohort) before drawing big conclusions from blended averages.
• Use a calculator that references this term (e.g., MER Calculator) to sanity-check assumptions.
• Read the related guide (e.g., MER (blended ROAS): how to use it without fooling yourself) for context and common pitfalls.

Where to use this on MetricKit