Platform · Metrics · MER
MER: Marketing efficiency ratio
Total revenue divided by total marketing spend. The blended truth when platform ROAS is lying to you.
What it is
Marketing efficiency ratio, sometimes called blended ROAS, is all revenue over all marketing spend in a period. It does not care which platform claims the sale. When every channel reports 5× and the company is not 5× more efficient, MER is the metric that catches it.
Why it is worth tracking
Privacy, multi-touch journeys, and marketplace checkouts make last-click ROAS a poor compass. MER tells Operators whether the whole mix is getting more or less efficient. It is the adult in the room when each dashboard is trying to take credit.
How to read it
A single number is not a brief. These splits are what change the work.
Platform ROAS up, MER down
Channels are stealing credit from each other, or you cut a growth channel that fed the rest. Do not scale the “winning” platform blindly.
MER stable, CAC improving
The mix is healthier. You can test more volume without waiting for a perfect in-platform story.
MER down in a festival window
Expected if you bought share of voice. Judge the peak on contribution and new customers, then return to always-on MER.
What the Operator does
Diagnose, act, then draft. The stats pick the job. Brand voice stays locked.
Diagnose
The Operator puts MER next to in-platform ROAS, spend mix, and new-customer volume. Divergence is the diagnosis, not a single dashboard.
Act
Rebalance spend when MER falls while one platform’s ROAS inflates. Keep a floor on prospecting even if its ROAS looks worse. Treat festival MER as a separate chapter.
Draft
Draft the work that improves blended efficiency: better prospecting creative, stronger offer architecture, and CRM that captures demand paid media already paid for, instead of more retargeting ads that recapture the same sale.
Example brief
“Meta ROAS is 4.2× but company MER fell from 3.1× to 2.4× after we cut Google and Klaviyo. Draft a 4-email post-click sequence and 6 Google RSA variants for the same hero SKUs so we can put spend back into the mix without another retargeting clone.”
Paste a brief like this into a Basis Operator. Connected account context and brand rules apply automatically.
Related metrics
Read it with these, or you will optimize the wrong surface.