Most B2B case studies are self praise in disguise. They have no problem in them, no numbers, and no customer speaking in their own words. Below is a section by section structure for how to write a case study, the interview questions that produce usable material, what to do when the client will not publish results, and an honest note on when a case study is a waste of time.
Key takeaways
- A case study is not a description of what you did. It is the customer's story, and you are the tool in it, not the hero.
- According to the B2B Content Marketing Benchmarks 2025 research by the Content Marketing Institute, based on 980 B2B marketer responses, 75 percent use case studies and 53 percent rate them among the most effective formats, second only to video at 58 percent.
- The structure that works has six parts: who, what was broken, what you did, what came out of it, a customer quote, and one line saying who this applies to.
- Six hundred to nine hundred words is enough. Longer and nobody finishes it, shorter and the numbers have no room.
- When a client will not publish revenue, use percentages, indices or operational metrics. There is always a number you are allowed to print.
- Ask for permission in writing and in advance, ideally in the project contract. After delivery is the worst possible moment.
Why does a case study beat a testimonial?
Because it can be checked. A testimonial says you are good. A case study shows how it went, which means a reader can decide for themselves whether it applies to them.
The difference is credibility. "Great collaboration, highly recommended" could be written by anyone and is read by no one. A paragraph saying a factory had spent three months trying to recruit operators and filled every position within six weeks of running a recruitment video gets read by everybody with a hiring problem.
The research agrees. The Content Marketing Institute b2b content marketing benchmarks for 2025, based on 980 responses, found that 75 percent of B2B marketers produce case studies and 53 percent rank them among their most effective content. Only video scored higher at 58 percent, which is the argument for producing both versions from the same project.
What structure should a case study follow?
Six parts in this order. The length in brackets is what we find readable in practice.
- Who and where from. (2 to 3 sentences) Company, industry, size. Without it the reader cannot tell whether this is their situation.
- What was broken. (100 to 150 words) A specific problem with numbers and a timeframe. Not "they wanted better communication" but "they had twenty minutes at a trade fair to explain the technology and people walked off after five".
- What you did. (150 to 250 words) Decisions, not a task list. What you chose not to do is more interesting than how many days you spent editing.
- What came out of it. (100 to 150 words) Numbers with a period and a baseline. A percentage without a before and after is worthless.
- The customer quote. (2 to 4 sentences) In their own words, even when they are not polished. The lack of polish is what makes it believable.
- Who this applies to. (1 to 2 sentences) One line telling the reader whether this is their case. Almost everyone leaves it out and it is the most useful sentence in the piece.
That totals 600 to 900 words. If you are heading for two thousand, you are writing about yourself. How to build the narrative line that holds it together is in our article on how to write a brand story.
Where does the material come from?
From an interview with the customer, not from your own memory. Thirty minutes of recording replaces three hours of guessing and fills the text with sentences you would never have invented.
Eight questions we use and you can copy:
- What was happening three months before you called us?
- What had you tried before, and why did it not work?
- Who inside the company was against it, and what convinced them?
- What surprised you along the way, good and bad?
- Which moment was the most uncomfortable?
- What changed in the numbers, and since when do you know that?
- What changed in how your company runs this now?
- Who would you recommend this to, and who should stay away?
Questions three and five do the heavy lifting. A case study that admits one thing went wrong during the project reads ten times more credibly than a smooth text where everything went to plan. Nobody believes everything went to plan.
What if the client will not share numbers?
Use a different number. Revenue and margins are sensitive almost everywhere, but around them sits a whole supply of metrics nobody minds publishing.
What usually works: a percentage change instead of an absolute sum, operational figures such as time to process an enquiry or days to fill a role, audience numbers such as reach, completed views or inbound enquiries, and internal time saved. If none of that passes, there is still the anonymised version: "a components manufacturer for the automotive industry with 120 employees". It loses force, but it beats nothing.
One rule we do not bend: a number without a period and a baseline does not belong in a case study. "Up 240 percent" with no timeframe and no starting point is filler, and an experienced reader spots it instantly.
How do you ask for permission without the awkwardness?
In advance and in writing, ideally inside the project contract. Asking after delivery hands the client a chance to say no at the exact moment they are happiest.
We handle it with two sentences in the contract: one says the supplier may use the project as a reference including visual material, the other gives the client the right to approve the exact wording before publication. It reassures the client that nothing goes out behind their back, and it protects you from the silence that follows when your contact person leaves six months later.
Video is stricter. You also need consent from everyone on camera, and when filming inside a plant, confirmation that nothing appears in shot that should not, whether that is drawings, screens with data or unreleased prototypes. How this gets handled in the brief is in our text on the video production brief.
When is a case study not worth writing?
When the project is too small, too fresh, or too similar to ten others already on your site. We admit this reluctantly, because case studies are the cheapest content we know how to produce.
Too fresh means the results are not in yet. A case study written a month after delivery contains impressions only, and readers can feel it. Wait three to six months even when it hurts. Too similar means the tenth study about the same kind of project convinces nobody and just takes up space. Five different ones beat fifteen identical ones.
And one more admission: a case study almost never brings anyone to your website. It is not search content, it is the content that closes someone who is already there. So never build it as a traffic source, build it as sales support. Our own projects are in the portfolio, and how we work on the concept behind them is on our creative services page.
Frequently asked questions
How long should a case study be?
Six hundred to nine hundred words in writing, and 90 to 120 seconds on video. Longer pieces only get finished by people who have already decided, and they do not need convincing.
Should a case study include the price?
It does not have to, but a range helps. A reader who cannot tell whether this was a two thousand or a twenty thousand euro project cannot place you and tends to stay quiet. If you cannot print a sum, at least give the timeframe or the team size.
Is a video case study worth it?
Yes, if you film it during the project rather than afterwards. A customer interview after delivery is cheap and quick, but footage from the process cannot be recreated. The difference between a case study video and a showreel is that a showreel shows what you can do, while a case study shows what it changed.
Where should case studies live on the website?
In their own section, one page per project, linked directly from the service page they belong to. Case studies buried in a blog disappear, and your sales people cannot find them mid call.
If you want a case study worth reading and have no time for the interviews and the writing, get in touch through our contact page. If you would rather write it yourself, the structure above is the whole recipe and you are welcome to it.
