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Content/Frameworks/Measurement

Acquisition MER. The new-customer standard.

Blended MER includes returning customers your acquisition spend did not buy. aMER isolates new-customer revenue per dollar of paid media. Plug your numbers in to see the gap between what blended is telling you and what acquisition is actually doing.

⌘ Framework·Interactive· NMaintained by Nathan Perdriau
Try it on your numbers

Calculate your aMER vs blended MER.

Drop in your last period's total revenue, returning customer revenue, and paid media spend. The tool shows both ratios side by side and highlights the gap blended is hiding.

Your inputs

A$
// All revenue inside the reporting period
A$
// Subscriptions, repeat orders, email-driven repeats inside the period
A$
// Total ad spend held accountable to acquisition

The two reads

// Blended MER
3.33x
Total rev ÷ ad spend
// Acquisition MER
2.00x
New customer rev ÷ ad spend
Blended is overstating acquisition by 40.0%

Your blended MER is 40.0% higher than your aMER. If acquisition decisions are being made against blended, you are reading the wrong number. New customer revenue divided by spend is the read.

// New customer rev = Total rev − Returning rev · Maths runs locally, nothing sent

If blended MER is healthy and aMER is not, you are funding retention with acquisition dollars and calling it growth.

aMER is total new-customer revenue divided by paid media spend in the same period. It strips out subscriptions, post-purchase upsells, email-driven repeat orders, and everything else the returning customer base contributes. What is left is the question you actually want paid media to answer: did the spend buy new buyers, at what efficiency.

Why blended hides the problem.

Take a brand running at 3.0 blended MER with 60% returning customer revenue. The acquisition layer is doing closer to 1.2 MER on new buyers. If gross margins are 50%, those two reads are not in the same conversation. The brand isn't failing. The read is. And the read decides where the next dollar goes.

The hierarchy in one line.

  • aMER is the primary KPI for whether acquisition is healthy.
  • Blended MER is a finance metric for cashflow and spend ceiling planning.
  • Incrementality tests (geo-lift, holdout) sit underneath both as the upper bound on causal claims.
If this matches how you think

Run the same diagnostic on your own account.

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