Growth marketing is a genuine discipline: run structured experiments across the whole funnel, keep what works, discard what does not, and compound. It has one prerequisite that rarely appears in a pitch. Experiments need enough traffic and enough conversions to distinguish a result from noise, and most businesses buying this do not have them. Without that volume the method degenerates into a series of confident conclusions drawn from very small numbers.
Ask what volume their method needs, before anything else
A credible growth agency will tell you how many conversions a month they need to read a test, and will say plainly if you do not have them. One that does not raise it is either not running real experiments or is going to report noise as insight. This is the single question that separates the discipline from the vocabulary, and it can be asked in the first ten minutes.
The whole funnel means access to the product, not just the ads
Growth work touches onboarding, activation, retention and pricing as well as acquisition, and that requires access to the product team and to product data. If the engagement is scoped to advertising and landing pages, it is performance marketing with a different name, which is a fine thing to buy and should be priced as such.
Retention is usually where the leverage is, and nobody sells it
Improving how many customers stay is generally cheaper and more durable than acquiring more, and it is harder to sell because it looks like product work rather than marketing. An agency that examines your retention curve before proposing an acquisition budget is taking the discipline seriously. One that proposes channels in the first meeting is selling media buying.
Insist on the losing experiments being reported
A real program has a high failure rate: most ideas do not work, and the value is in finding the few that do. A report showing an unbroken run of successes describes either an extraordinary team or a measurement standard nobody is applying. Ask for the full record, including the tests that were stopped and why, and read the proportion rather than the wins.
Decide who owns the learning
The point of the method is the accumulated knowledge of what works for your business, and that should end up documented in a form your team can use after the engagement ends. If the learning lives in the agency's heads and its slide decks, you have rented results rather than built a capability, and the second is what this discipline promises.
Questions people ask about growth marketing agencies
What is growth marketing, exactly?
Structured experimentation across the whole funnel, acquisition through retention, keeping what works. The method is real; its prerequisite is enough traffic and conversions to read a result, which most buyers do not have.
How much traffic do we need?
Enough conversions, not visitors, and the honest number depends on the size of change you want to detect. Ask the agency what their method requires, and treat an evasive answer as the answer.
How is it different from performance marketing?
Scope. Growth work touches onboarding, activation, retention and pricing, which needs access to the product and its data. An engagement limited to ads and landing pages is performance marketing under a newer name.
What should we get at the end?
A documented record of what was tried, what worked and what did not, in a form your team can use. If the learning stays with the agency you rented results rather than building the capability the method promises.