MER (Marketing Efficiency Ratio)

The formula, an illustration, and a calculator that runs it on your own figures.

MER is the number the audit reconciles to the management accounts first, because it is the only marketing ratio that cannot be improved by moving spend between platforms. Shifting budget from Google to Meta changes both platform ROAS figures and leaves MER exactly where it was, unless revenue actually moved. That makes it the honest baseline against which every attribution claim is tested.

It also exposes the costs that dashboards leave out. Platform ROAS does not know about the agency retainer, the markup inside the media invoice, the tooling stack or the freelancer who builds the creative. MER does, and the gap between the two ratios is often the first margin finding of the engagement.

A good MER depends on contribution margin, not on an industry average: the ratio has to clear the inverse of the margin before marketing is paying for itself. The audit therefore reads MER beside the margin per order. Across the 74 audits a median 18.7% of marketing spend was leaking, and that is the part of the denominator an audited fix removes.

Published cases where MER was at the center of the finding, each with the audited annual figure.

• B2B SaaS

  A $1.2M ad budget hid a 40% wasted impression rate

  −$74k a year, findings in 7 days.

  Read the case →
• B2B SaaS

  Content spend had no path to revenue

  −$36k a year, findings in 7 days.

  Read the case →
• Pharma

  Seasonal media weight ignored when the category actually converted

  +$60k a year, findings in 7 days.

  Read the case →
• Manufacturing

  Trade show spend had no attributable pipeline

  −$41k a year, findings in 6 days.

  Read the case →
• Pharma

  Detailing and sample spend produced no prescribing lift

  −$64k a year, findings in 7 days.

  Read the case →
• Pharma

  Congress and KOL sponsorship showed no measurable return

  −$88k a year, findings in 7 days.

  Read the case →