Metric Explainers
What common ad numbers like CAC and ROAS actually mean, how to work them out, and the mix-ups that lead teams astray.
Articles in this collection
14 articlesCPA vs CAC vs CPP: stop mixing them in one deck
CPA counts actions, CAC counts new customers, CPP counts platform claims. Which one governs budgets, and one query that computes all three.
Blended CAC vs. Channel CAC — Which One Goes to the Board?
Channel-reported CAC is almost always cheaper than blended CAC, and both numbers are correct. Here's how to know which one belongs in which conversation.
MER Explained, With the SQL
Marketing Efficiency Ratio sidesteps attribution disagreements entirely. Here's the formula, a worked example, and the query that computes it from a warehouse.
Attribution Windows: 1-Day Click, 7-Day View, and Why Your Numbers Moved
Every ad platform ships a different default attribution window. Here is what each window setting actually changes, with worked examples.
Incrementality vs. Last-Click for Teams Without a Data Scientist
A holdout test is the only way to know an ad's true causal effect. Here is a lightweight version any team can run without a dedicated experimentation function.
LTV:CAC Is a Ratio, Not a Target — How to Read It Honestly
A 5:1 LTV:CAC ratio means very different things depending on payback time. How to read the ratio alongside the number that actually matters.
Breakeven ROAS From First Principles: Margin, Fees, Shipping and the Floor Under Every Target
One division sets the floor beneath every target you will ever set. Deriving breakeven from the full variable stack and running it as a bidding guardrail.
Cohort Payback Curves: Why Month-0 ROAS Misleads Repeat-Purchase Brands
Snapshot ROAS judges a movie by its first frame. Group customers by acquisition month, read payback as a crossing point and separate retention.
Discount-Adjusted Metrics: How Sale Events Inflate ROAS While Destroying Contribution
Revenue triples and profit misses anyway. Margin compression, pull-forward holes and price-anchor erosion — and the reporting that prices each sale honestly.
Contribution-Margin ROAS: The Only ROAS That Survives a CFO Review
Revenue ROAS answers a question finance never asked. Rebuild it on contribution margin, with the cost lines people forget and the SQL that computes it.
New vs. Returning Customer ROAS, and Why Blended Hides an Acquisition Problem
A stable blended ROAS can conceal acquisition falling apart underneath it. Split the numerator by customer type and the trend you actually need to see appears.
Payback Period vs. LTV:CAC — Which One Actually Gates Your Ad Budget
LTV:CAC says whether a customer is worth acquiring; payback says whether you can afford it this quarter. Only one of them is a budget constraint.
RTO and COD in Indian D2C: Your ROAS Is Wrong Until Delivery Confirms
A COD order is a promise, not revenue. With RTO at 15-35%, order-time ROAS overstates reality by up to a third. How to measure delivered ROAS instead.
Frequency, Reach and Saturation: Reading the Curve Before You Scale Spend
Scaling spend in a finite audience buys frequency, not reach. How to read the three curves together and tell which wall your campaign has hit.