Metric sprawl is its own failure mode. Dashboards with twenty tiles get glanced at, not used. The discipline is knowing which question each metric answers — and refusing to let a metric answer a question it can't.
MER — “Is marketing working overall?”
Marketing Efficiency Ratio = total revenue ÷ total marketing spend. All channels, all costs, no attribution games — it can't be gamed by window-shopping because it doesn't use windows. If you spent $40K across everything last month and did $200K in revenue, MER is 5.0. Watch its trend: a falling MER while spend rises is the classic signature of saturating channels. MER won't tell you which channel is the problem — that's not its job. It's the smoke alarm, not the inspection.
CAC — “What does a customer cost, really?”
Customer Acquisition Cost = total sales + marketing cost ÷ new customers. Two honesty rules. First, use fully loaded cost — salaries, tools, agency fees, AI spend — not just ad budget; a $50 “CAC” that ignores the $15K/month team is fiction. Second, always read CAC against LTV. CAC of $400 is excellent for a $4,000-LTV product and fatal for a $300 one. The ratio (LTV:CAC of 3+ as a rough floor) is the number; CAC alone is half a number.
ROAS — “Is this specific campaign worth its budget?”
Return on Ad Spend = attributed revenue ÷ ad spend, per campaign. This is the workhorse for in-platform decisions — and the most abused number in marketing, because it inherits every attribution sin from the platform reporting it. Use it comparatively (campaign A vs. campaign B on the same platform, same window), never absolutely (“our ROAS is 4 so we're profitable” — you don't know that). And when a decision is expensive, upgrade from ROAS to incrementality before you scale.
The hierarchy in practice
- MER falls → something systemic changed. Investigate before reallocating.
- MER fine, CAC rising → mix problem: a cheap channel saturated and spend slid to a dearer one.
- MER and CAC fine, one campaign's ROAS sags → routine optimization; kill or fix the creative.
Three numbers, three altitudes, three different meetings. Most “what's working?” arguments dissolve the moment everyone agrees which altitude the question lives at.
Where Mayaa fits
Mayaa's daily briefing leads with exactly this hierarchy — MER trend first, fully-loaded CAC against your LTV, then campaign-level ROAS only where a decision is pending — written in plain English by the analytics agent, with every number's definition one click away. Ten-tile dashboards impress in demos. Three honest numbers run companies.
Want this run for you? The team that wrote these posts is the team that does the work.
Start free trial
