Telling a Growth Engine From a Spending Habit

Two companies both grew revenue 30 percent. One built something that compounds. The other spent more money to get more customers at steadily worse economics.

From the outside, and often from inside, these look identical for years. Here’s how to tell them apart.

Test one: the ratio between spend growth and revenue growth

Plot marketing spend and new customer revenue over eight quarters and compare their growth rates.

If spend grew 40 percent and revenue grew 30 percent, the business is buying growth at a deteriorating rate. That’s not necessarily wrong, plenty of businesses correctly buy growth, but it’s a decision with a shelf life and it should be understood as one.

If revenue grew faster than spend, something is compounding. Find out what, because that’s the asset.

Test two: acquisition cost by cohort, not in aggregate

Aggregate CAC hides the trend. Break it out by quarter of acquisition and look at the slope.

Rising CAC with flat conversion means the market is getting more expensive or the targeting has loosened to chase volume. Rising CAC with rising average order value can be fine. Rising CAC with flat order value and falling retention is a business consuming its own future.

Test three: what happens when a channel goes dark

The only test that produces causal evidence rather than correlation.

Pause a meaningful channel for two weeks and watch total revenue, not that channel’s revenue. If total revenue barely moves, that channel was largely harvesting demand that already existed and taking credit for it.

Almost nobody runs this because it feels like deliberately losing money. It is dramatically cheaper than funding something ineffective for another year, and it is the single most informative two weeks available in marketing.

Test four: the rented-to-owned ratio

Split demand into what stops when the money stops and what doesn’t.

Paid search, paid social and affiliates are rented. Organic rankings, an engaged list, brand recall, review inventory and referral flow are owned.

A business at 90 percent rented has no floor. Cut the budget and revenue follows immediately. A business with real owned demand can absorb a downturn, which is exactly the scenario where the distinction stops being academic.

The ratio also predicts what happens under new ownership, because new ownership frequently arrives with a mandate to improve margin.

Test five: retention by acquisition channel

Blended retention is one of the most misleading numbers in business, because it averages together customers with completely different characteristics.

Break churn out by how the customer was acquired. It’s common to find that the cheapest channel produces customers who churn at two or three times the rate of the rest, which means the cheap channel is the expensive one and the reported CAC was never the real cost. Why lifetime value has to sit next to acquisition cost.

What each answer implies

Compounding. Owned demand is growing, CAC is flat or falling, retention is consistent across channels. Protect it, understand what’s driving it, and be careful about changes that optimize short-term efficiency at its expense.

Purchased but healthy. CAC is rising modestly, unit economics still work, payback is acceptable. This is a legitimate strategy. It requires continuous funding and it needs a plan for building owned demand before the paid economics stop working.

Purchased and deteriorating. CAC rising, retention falling, everything rented. Revenue growth is masking a business getting worse per unit. The correction usually arrives all at once, and it arrives during the first budget cut.

The useful thing about running these five is that they take days rather than months, and the answers change what you’d pay, what you’d plan, and what you’d fix first.