How to tell if your marketing agency is doing a good job

Most business owners cannot actually tell if their marketing agency is doing a good job. Not because they are not paying attention, but because the agency controls the story. You get a monthly report full of impressions, reach, engagement, and a ROAS number with no context, and it all looks busy and vaguely positive. So you keep paying, month after month, on a gut feeling that something is working. Sometimes it is. Often it is not, and the report is designed so you cannot tell the difference.

Here is the short version. A good agency can be measured on one thing: does it cost you less to acquire a customer than that customer is worth, and is that gap getting better over time. Everything else on the report is decoration. Once you know that, auditing your own agency takes an afternoon, not a spreadsheet and a data science degree.

What a good agency actually does

Strip away the jargon and a paid ads agency has one job. Bring in customers for less than those customers are worth to you, and do it at a scale that grows your business. That is it. Creative, targeting, testing, reporting, all of it is in service of that single outcome.

So a good agency does a few specific things you can look for:

It knows your real numbers. Your cost per purchase, your customer lifetime value, your margins. If they cannot tell you what a customer costs to acquire and what one is worth, they are guessing.
It reports on money, not motion. Customers, cost per customer, revenue, profit. Not vanity metrics dressed up to look like progress.
It gives you access. You own the ad account, the pixel, and the data. Always.
It tells you when something is not working. A good partner brings you bad news early. A bad one hides it until you go looking.

If your agency does those four things, you are probably in good hands even if a given month is soft. If it does not, a great month is just luck you are paying a retainer for.

The one number that cuts through everything

Forget the dashboard for a second. There are only two numbers that decide whether your marketing is working:

What does it cost you to acquire a paying customer? That is your cost per purchase, or CPA.
What is that customer worth to you over their lifetime? That is your LTV.

If your CPA is comfortably below your LTV, the marketing is working. If it is not, it is not, no matter how good the report looks. This is the whole game, and a good agency will talk to you in exactly these terms. A bad one will steer you toward impressions and reach precisely because those numbers never make them look bad.

You do not need to take anyone’s word for it either. You can run these yourself in two minutes with a breakeven ROAS calculator and an LTV to CAC calculator. Punch in your own numbers, then ask your agency why theirs do or do not match. Watching how they answer that question tells you more than any monthly report ever will.

The green flags

You are probably in good hands if:

They can state your cost per customer and your LTV from memory, and they care about the gap between them.
Reports lead with customers and revenue, and only mention reach and impressions as supporting detail.
They proactively tell you what they tested, what failed, and what they are changing because of it.
They push back on you sometimes. An agency that agrees with everything is managing you, not your ads.
Your results survive them going on holiday. A real system does not collapse the week the account manager is away.

The red flags that actually matter

Some warning signs are worth reacting to immediately:

They will not give you full access to your own ad account. This is the big one. If the agency runs everything through their own account and will not add you as an admin on yours, you do not own your data, your pixel history, or your audiences. The day you leave, you leave with nothing. This is sometimes rage searched for a reason. It is a genuine red flag, not a technicality.

The report is all vanity metrics. Impressions, reach, engagement rate, and video views are easy to make go up and have almost nothing to do with revenue. If those are the headline numbers every month and cost per customer is buried or missing, the report exists to reassure you, not to inform you.

They cannot give you a clean cost per purchase. If you ask what it costs to acquire a customer right now and you get a vague or shifting answer, one of two things is true. Either they do not know, or the tracking is broken and nobody has fixed it. Both are problems. On Meta today, broken tracking is everywhere, and a good agency treats fixing it as job one, not an excuse.

They blame iOS and the algorithm for everything. ATT and SKAdNetwork made attribution harder, that part is true. But a good agency responds by sending clean server side data through the Conversions API and tools like RevenueCat so Meta can still optimise on real purchases. A bad agency uses “iOS killed tracking” as a permanent excuse for why they cannot show you results.

Nothing ever changes. Same three ads, same audiences, same setup for six months. Paid ads decay. If there is no visible testing and no evolution, you are paying a retainer for autopilot.

How to audit your agency in an afternoon

You do not need to confront anyone. Just run this quietly:

Ask for admin access to your own ad account and pixel. Watch how fast and how willingly it happens.
Ask one question: what does it cost us to acquire a customer right now, and what is that customer worth. A good agency answers in one sentence.
Run your own breakeven ROAS and LTV to CAC numbers and compare them to what the agency reports.
Do a test purchase and check it shows up correctly in Events Manager. If your own conversions are not tracking, no report from anyone is trustworthy.
Look at the last three monthly reports side by side. Are customers and revenue improving, or just impressions?

If you get clean access, a straight answer, numbers that match, working tracking, and real improvement over time, keep your agency. They are earning it. If two or three of those come back wrong, you do not have a marketing problem. You have an agency problem.

Bottom line

A good marketing agency makes you more money than it costs, can prove it in plain numbers, and hands you full ownership of your own data while doing it. A bad one keeps you looking at the metrics that never make it look bad. The difference is not hard to see once you know where to look, and you do not have to be a marketer to check.

If you have an agency and something feels off but you cannot put your finger on it, that is usually exactly what I pull apart on a teardown call. I will look at your account, your tracking, and your real cost per customer, and tell you straight whether your ads are working or whether your reports just look like they are.