Comparison · 9 min
Growth consultant vs. marketing agency: which do you actually need?
This is written by someone who sells one of the options on this list, so read it with that in mind. I have tried to make it the comparison I would want if I were the one buying, which means being specific about when the answer is not me.
The short version
Pick based on where your business is losing money, not on which category sounds most impressive. The most expensive mistake in this market is buying demand when the problem is downstream of demand.
| If your problem is… | Hire… |
|---|---|
| Nobody knows we exist, and everything after that works | A marketing or SEO agency |
| Our site is genuinely old and everything else is fine | A web agency |
| One specific repetitive process is eating our week | An automation consultant |
| We need a strategic decision made, not built | A business consultant |
| Demand arrives and we lose it somewhere, or we cannot tell | Growth engineering |
Marketing agency
An agency is paid to produce activity in one channel and is measured on leads delivered to the top of your funnel. That is a legitimate service, and if your genuine constraint is that not enough people know you exist, it is the right purchase.
The structural issue is that an agency is uninterested in what happens after the form submit, because nothing in their contract or their reporting covers it. If your leads are dying in an inbox, more leads make your problem worse and their numbers better. Neither party is acting in bad faith; the incentives just do not overlap where you need them to.
Hire one when: your conversion rate is healthy, your response time is measured in minutes, your follow-up runs without anyone remembering, and you can name the channel that produced last quarter’s revenue. Then buying more demand is exactly right.
Web agency
A web agency ships a site and moves on. The site is a deliverable rather than a system: usually not wired to your CRM, with follow-up as an afterthought, and with nobody having instrumented which pages produce inquiries.
Hire one when: the website is genuinely the constraint and the rest of your path already works. That is rarer than the number of website rebuilds sold each year would suggest, but it does happen, and when it does a good web agency is faster and cheaper than anything else on this list.
SEO agency
SEO answers exactly one question: can people find you. It cannot tell you whether the people who find you convert, whether they get a reply, or whether they buy.
It is also the slowest-returning thing you can buy. Four to six months minimum before you can judge it fairly on a new or low-authority domain, and longer in competitive service categories. Anyone promising faster is either guessing or targeting terms nobody buys from.
Hire one when: your conversion and follow-up are already solid and you want a channel that compounds instead of one you rent monthly. Do not hire one when: you are hoping traffic will fix a business that is currently losing the traffic it already has.
Automation consultant
Automation makes an existing process faster. If the process is wrong, automation makes the wrong thing happen more often and with fewer humans watching it happen.
The common failure mode is that automation consultants arrive with a tool — Zapier, Make, a particular CRM — and fit your business to it, because that is what they know and what they are fast at. Sometimes that is fine. Sometimes you end up with forty automations nobody documented and nobody monitors.
Hire one when: you have a clearly defined, genuinely correct process that is being executed by hand, and you want it executed faster.
Business consultant
A consultant produces analysis and a recommendation. Then you have to find someone to build it, and the person who builds it did not do the analysis, so a meaningful amount of the reasoning is lost in translation.
Hire one when: the decision itself is the hard part — market selection, pricing strategy, acquisition, an organisational restructure. Those are real problems and they are not what growth engineering is for.
Growth engineering
Growth engineering treats the path from first search to closed customer as one system, diagnoses which checkpoint is actually failing, and builds the fix in code and configuration. The deliverable is a working, instrumented system rather than a campaign or a document.
Hire this when: demand exists and you are losing it somewhere, or when you genuinely cannot tell which of the five things above you need. That second case is why the engagement starts with a diagnosis rather than a build.
Do not hire this when: you are pre-revenue with no demand to route, or when you know exactly what the problem is and it sits cleanly inside one of the categories above. In those cases the specialist is faster and cheaper, and you should hire the specialist.
The honest summary
Each category can be effective at the problem it is designed to solve. The failure is in the matching: for example, a business with a follow-up constraint buying more demand before that constraint is measured.
Before hiring anyone, run the nine-checkpoint diagnostic. It takes an afternoon, it costs nothing, and it will tell you which of these six paragraphs applies to you.