Most small businesses have dozens of good case studies sitting in their job history. The kitchen fitted in a week when the last firm took a month. The accountancy client whose VAT return stopped being a quarterly panic. The problem is rarely a lack of material. It is finding the hours to interview the customer, shape the story and write it up properly. This guide walks through how to write a case study for your business, start to finish, and where an AI assistant like Claude helps without putting words in anyone's mouth.
Why should a small business bother with case studies at all?
Reviews are now the default way people check a business before contacting it. BrightLocal's Local Consumer Review Survey 2026 found that 97% of consumers read reviews for local businesses, and that 41% "always" read them when browsing, up from 29% the year before. That survey sampled 1,002 US adults, so treat it as a direction of travel rather than a UK census, but the pattern will feel familiar to anyone running a UK trade or service business.
The same survey found that 74% of consumers look for reviews written in the last three months. Freshness matters. A steady habit of one case study a month keeps your proof current in a way a single testimonials page written years ago never will.
What is the difference between a case study and a testimonial?
Think of it this way. "Brilliant service, would recommend" is a testimonial. "A Bristol café owner was losing Saturday trade because her booking system kept double booking tables. Here is what changed and what her Saturday covers look like now" is a case study. The second one is useful to every other café owner with the same headache.
You need both. If you have not yet sorted where your reviews live on your own site, the guide on adding reviews to your website covers widgets and placement. Case studies then sit on top as the detailed proof.
Which jobs make the best case studies?
Run through your last six months of work and score each job on four things:
- Clear problem. Could you describe what was wrong in one sentence?
- Visible result. Is there a number, a photo, or a specific change the customer noticed?
- Willing customer. Were they happy, and are they the type to say yes to a ten minute call?
- Commercial fit. Is this the kind of work you want to win again?
A modest job that scores well on all four beats a huge project that you would rather not repeat. If you are an electrician who wants more EV charger installs, write up the EV charger installs, even if the rewire paid more.
How do you interview a customer for a case study?
A short script works better than an improvised chat. Try these, in order:
- What was going wrong before you got in touch?
- What had you already tried?
- Why did you pick us over the other options?
- Was there anything during the job you did not expect?
- What is different now? Is there a number that shows it?
- What would you tell a friend thinking about using us?
Record the call (many video call tools and phone apps can transcribe) or send the questions by email for customers who prefer to write. Ask for photos at the same time. Before and after images carry a surprising amount of weight on trade sites.
How do you use Claude AI to write a case study from your notes?
A prompt along these lines works well:
Using only the transcript and notes below, write a case study of around 600 words with these sections: the customer and their problem, why they chose us, what we did, the result. Use direct quotes from the transcript where they fit, word for word. Do not invent any numbers, dates or claims. At the end, list every figure and quote you used and the line of the transcript it came from, then list any gaps where a fact would help.
That last instruction is the important one. It turns Claude into a checker as well as a writer, and it makes your review take minutes rather than a full reread. If you set up a Claude Project with your house style, a sample case study you like and your consent checklist, every new write up starts from the same baseline.
Once the long version is approved, ask Claude for shorter cuts from the same text: a 150 word version for a service page, a social post, and a paragraph for your next email. If you plan content weekly, slot these into an AI content calendar so one interview feeds a month of posts.
What structure should a business case study follow?
| Section | What goes in it | Rough length |
|---|---|---|
| Headline | The result, in plain words, with sector or town | One line |
| The problem | Who they are, what was going wrong, what it cost them | 100 to 150 words |
| Why you | What made them choose you, in their words | 50 to 100 words |
| The work | What you did, any obstacles, how long it took | 150 to 200 words |
| The result | What changed, with any figures the customer confirmed | 100 to 150 words |
Write the headline last. "New boiler fitted" tells nobody anything. "Victorian terrace in Sheffield, warm in every room for the first winter in years" tells the right reader this is about them.
What are the legal rules for case studies and reviews in the UK?
The ASA's CAP Code guidance sets out four practical points. Hold evidence the testimonial is genuine. Hold the person's contact details. Get permission. Make sure any claims inside the testimonial are not misleading, and do not edit quotes in a way that changes their meaning.
The Digital Markets, Competition and Consumers Act went further. According to CMS's summary of the fake reviews ban, the rules came into force on 6 April 2025 and breaches can lead to fines of up to 10% of annual global turnover. The ban covers commissioning fake reviews, hiding the fact that a review was incentivised, and misleading practices like suppressing negative reviews or cherry picking positive ones.
For case studies, that means three habits. Never let Claude write praise that the customer did not give. If you offered a discount or gift for taking part, say so on the page. And keep the signed consent and the original transcript together. If customer data is going into an AI tool, check it against an AI data protection checklist first, and strip out anything you do not need, such as home addresses or phone numbers.
How do you get customers to agree to a case study?
Timing matters most. The week after a job is finished, when the customer is still pleased, is the moment to ask. Six months later the detail has faded and the goodwill has cooled.
Be specific about the effort involved: "a fifteen minute call next week, and you'll see the write up before anything is published." For business customers, point out what they get from it. A case study on your site is often a link back to their own business and a bit of free publicity in their sector.
Some customers will not want their name used. That is fine. An anonymised case study ("a family run dental practice in Kent") is weaker than a named one but still useful, as long as the details are real and you are not implying a specific endorsement you do not have.
How often should a small business publish case studies?
The BrightLocal finding that 74% of consumers look for reviews from the last three months is a good rule of thumb for case studies too. A page that shows a job from last month reads very differently from one where the newest example is from three years ago.
Build the process once. A consent template, a fixed interview script, a saved Claude prompt and a checklist for photos turn each case study into an hour or two of work rather than a day. The honest trade off is that someone still has to make the call and check the draft. AI handles the writing well, but it cannot replace a real customer conversation or your judgement on what is accurate.
Case Studies with Claude AI — FAQ
How long should a small business case study be?
Most small business case studies work best at between 400 and 800 words. That is long enough to cover the problem, what you did and the result, and short enough to read on a phone between jobs. A one-page web version with a headline result, three short sections and one customer quote is usually enough. If you work in a sector where buyers do more research, such as commercial building work or professional services, you can add a longer PDF version with drawings, timelines or costs. Do not pad it out. A short case study with one specific, checkable result beats a long one full of general praise. Claude can turn your interview notes into both a short and a long version from the same source material, so you only gather the facts once.
Do I need written permission to publish a customer case study in the UK?
Yes, you should get it. The ASA's guidance on the CAP Code says marketing must not feature a testimonial without permission, and that you must hold documentary evidence that it is genuine, plus contact details for the person who gave it. Using someone's name, photo or business details also brings in UK data protection rules. The simplest approach is a short consent form or email that names exactly what you will publish (name, company, photos, quote), where it will appear, and how they can ask you to remove it later. Keep that record with the interview notes. Show the customer the final draft before it goes live, and keep their approval email on file.
Can Claude AI write a case study without inventing details?
It can, if you control what goes in. Claude works from the material you give it, so paste in your interview transcript, job notes, quote and invoice details, and tell it plainly to use only those facts and to flag anything missing rather than filling the gap. Ask it to list every number and quote it used, with where each one came from in your notes, so you can check them in a minute. Never ask it to write a testimonial from scratch or to improve a customer's quote with new claims. The CAP Code expects testimonials to reflect what the person said, and since 6 April 2025 UK law has banned fake reviews, so invented praise is a real legal risk, not only an ethical one.
What questions should I ask a customer for a case study?
Ask questions that draw out a before and after story in the customer's own words. Good ones include: what was going wrong before you got in touch, what had you already tried, why did you choose us over the alternatives, what happened during the job that you did not expect, what is different now, and is there a number that shows it, such as time saved, bookings up or a lower bill. Finish with what you would tell a friend who was thinking about using us. Record the call with permission, or send the questions by email if they prefer. Claude can turn a messy transcript into a clean draft, but the raw answers need to come from the customer.
Where should I publish case studies to get the most from them?
Put the full version on its own page on your website, with a clear headline result and the customer's location or sector so people searching for similar work find it. Then reuse it. Link to it from the relevant service page, send it to prospects who are weighing up a quote, and cut it into a short social post or email. Claude can produce those shorter versions from the approved case study in one go. Keep every version consistent with the signed off original, and do not add new claims in the shorter cuts. If the customer has also left a review on Google or another platform, you can point readers there as independent backup for what the case study says.
