MER Analysis models what happens to blended efficiency and total profit when you scale spend. Its premise: MER almost always falls as spend grows, because organic revenue stays flat while the paid side expands, and a falling MER can coexist with rising profit. The metric that matters is total profit, not the ratio.
From four inputs (total revenue, marketing spend, gross margin, and the share of revenue that is paid): MER = total revenue divided by spend, ROAS = paid revenue divided by spend, and total profit = revenue times gross margin minus spend.
Two thresholds anchor the scenario. The ROAS needed to hold MER flat equals your current MER. The ROAS needed to break even on incremental spend equals 1 divided by gross margin; below that, every additional dollar loses money. The scaled scenario then adds spend at a chosen incremental ROAS, holds organic flat, and compares current versus scaled on MER, profit, and revenue mix, with a verdict: profit up while MER down means the added spend is worth it, both up means scale harder, profit down means stop.
No CSV. Four numbers you already know (total monthly revenue, marketing spend, gross margin percent, paid share of revenue) plus the scaled spend to test and an incremental ROAS assumption, either your current ROAS or a custom value. Scenarios encode into the URL for sharing.
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