How to Write a Case Study - Structure, Template and Example

Maciej Stolarski · August 17, 2026 · 9 min read

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A case study is a written account of one piece of work you did for one customer, told through the decision they faced and the result they got. Buyers ask for it by name when they are close to deciding, and most small businesses never publish one because the writing feels like it needs a research department.

It does not. A usable case study takes one interview of about thirty minutes, a page of notes, and a fixed structure you reuse every time. This guide gives you that structure, the questions that produce quotable answers, a template, and a worked example.

Table of contents

What a case study has to prove

A testimonial says you were pleasant to work with. A case study answers the harder question a buyer is asking silently: has this company handled a situation that looks like mine, and what actually changed.

Every case study therefore carries three burdens of proof.

  1. Recognition. The reader has to see their own situation in the opening. If a warehouse manager reads about a warehouse with the same problem, attention is earned in the first paragraph.
  2. Mechanism. The reader has to understand what you did and why, in enough detail that the result looks earned rather than lucky.
  3. Consequence. The reader has to see what changed, in the customer's terms - hours, orders, complaints, rework, waiting time, cost.

A case study that skips the mechanism reads like an advertisement. One that skips the consequence reads like a project log.

Pick the customer story that carries the most weight

Start with your most repeatable sale rather than your favourite client. Write down the three enquiries you receive most often, then find a finished job matching each one. Those are your first three case studies, in that order, because each does sales work every week rather than once.

A story is worth writing up when it meets four tests:

  • the starting problem is one other prospects also have,
  • the work is representative of what you actually sell, not an unusual favour,
  • something measurable changed, even if the measure is small,
  • the customer is willing to be named, or willing to be described precisely enough to be credible while anonymous.

Skip the job that went perfectly because the client was unusually well prepared. It reads as flattering and teaches the reader nothing.

Agree what you are allowed to publish

Settle this before you write, not after. Ask for four permissions at once: whether you may name the company, whether you may name the person and their role, which numbers may appear, and whether you may use their logo or a photo. Offer an anonymous version as the default fallback so that a no on naming does not become a no on the whole piece.

Send the finished draft for approval before publication. Approval comes faster when the client sees they are portrayed as the decision maker rather than as a passive beneficiary, so write it that way.

Run the interview that produces usable material

Record it with permission, keep it to half an hour, and ask about the situation before you ask about you. These nine questions produce nearly everything you need.

  1. What was happening in the business when you decided something had to change?
  2. How long had it been going on, and what did you try first?
  3. What was it costing you - in money, time, or something else?
  4. What made you start looking for outside help at that particular moment?
  5. What worried you about hiring someone for this?
  6. Why did you choose us over the other options you considered?
  7. What was the first thing that changed, and how soon?
  8. Where are you now compared with then? Any number you can share?
  9. What would you say to someone in the same position who is hesitating?

Question 5 is the one people skip, and it is the most valuable. The objection your customer names is the objection your next prospect is holding silently. Answering it inside a real story is far more persuasive than answering it on a sales page.

Question 9 usually produces the pull quote.

The six part case study structure

Use the same skeleton every time. Consistency makes the pieces faster to write and easier for a reader to scan across several stories.

  1. Situation - who the customer is, what they do, and the state of things before the work. Two or three sentences. Concrete industry, size, and location.
  2. Problem - the specific pain and its cost. Name what was breaking and what it was worth.
  3. What we tried and why - the reasoning behind the approach, including one option you rejected. Rejected options are what make the piece read as honest.
  4. The work - what happened, in sequence, with a timeline. Keep it operational.
  5. Result - the change, with a number where you have one and a before-and-after comparison where you do not.
  6. Customer's own words - one quote of two or three sentences, unedited beyond tidying filler.

Target 600 to 1000 words. A case study that runs to three thousand words stops being read at the point where the proof lives.

A case study template you can copy

Paste this into your notes and fill it in straight from the interview transcript.

  • Headline - customer outcome in plain words, with the number if you have one.
  • Summary box - client, sector, service delivered, timeframe, headline result. Four lines, scannable.
  • Situation - two to three sentences.
  • Problem - what it was costing, and how long it had run.
  • Approach - three to five steps, plus the option you rejected and why.
  • Result - before and after, with the measure named.
  • Quote - the customer's answer to question 9.
  • Next step - one link to the relevant service page or an enquiry form.

The summary box matters more than it looks. Many readers only ever read those four lines, so they must stand alone as proof.

A worked example for a service business

A three person cleaning company wants more office contracts. Its most common enquiry comes from an office manager whose current provider keeps missing tasks.

Headline. A serviced office cut cleaning complaints from eleven a month to one.

Situation. A serviced office in a mid-sized city, 40 desks over two floors, cleaned five evenings a week by a previous contractor.

Problem. The office manager logged around eleven tenant complaints a month, mostly kitchens and meeting rooms after busy days. Each took about fifteen minutes to handle - roughly three hours a month spent chasing a supplier she was already paying.

Approach. Adding a second evening cleaner would have raised the price by a third, so it was rejected. Instead the schedule was rebuilt around observed usage: kitchens and meeting rooms twice per evening, desks and floors on the existing rota, and a photographed checklist submitted each night.

The work. Week one, a usage audit. Week two, the new rota. From week three, the nightly checklist by email.

Result. Complaints fell to one a month by the second month and stayed there. Handling time dropped from about three hours a month to under twenty minutes. The contract price rose four per cent, approved on the basis of the checklist alone.

Quote. 'I stopped being the person who has to chase the cleaners. That is the part I would tell anyone who is hesitating.'

Every number there came from the interview. None required access to the client's accounts.

What to do when the client will not share numbers

Most small clients will not hand over revenue figures. That is not a blocker, because operational measures are often more persuasive to a buyer than financial ones.

Ask instead for a count, a duration, or a frequency:

  • how many complaints, errors, callbacks, or returns per month, before and after,
  • how long a recurring task took, before and after,
  • how many enquiries were handled per week without adding staff,
  • a percentage change where the absolute number is confidential.

'Complaints down from eleven a month to one' works without ever naming a revenue figure. Where you have nothing countable, use a precise before-and-after description of the process and label it as such. Precision reads as honesty; a vague percentage with no source reads as invention.

Where case studies belong in a content plan

Case studies are late-stage material, so they earn their place among your BOFU content rather than in top-of-funnel publishing. Map one to each main service and to the point in your customer journey content where a buyer is comparing suppliers.

They also age well. A story about a decision and its result stays true, which makes case studies among the most reliable evergreen content a small business can hold. Two or three a year is realistic for a small team, and treating them as one of your content pillars keeps them on the calendar rather than in the someday pile.

One interview also feeds several formats: the full write-up, a short post built around the pull quote, a slide for a proposal, and an answer you paste into email replies. That is content repurposing with no extra research.

Common case study mistakes

  • Writing about yourself. The customer is the protagonist. You are the supporting character with a method.
  • Hiding the numbers below the fold. Put the headline result in the title and the summary box.
  • Naming no obstacle. A story with no friction reads as fiction. Include what nearly went wrong.
  • Anonymising everything. 'A client in a certain sector' proves nothing. If naming is refused, be specific about size, industry, and location instead.
  • Waiting for a spectacular result. A modest, credible, well documented change converts better than a dramatic claim without a mechanism.

FAQ

How long should a case study be?

Between 600 and 1000 words for most small businesses. That is enough for situation, mechanism, and result, and short enough that the proof is still on screen when the reader decides.

What is the difference between a case study and a testimonial?

A testimonial is an opinion about working with you. A case study documents one project from starting problem to measured outcome, so it shows the reader how the result was produced.

Can I write a case study without the client's permission?

Publish an anonymous version describing sector, size, and situation, and confirm the arrangement with the client first. Named clients, quotes, logos, and specific figures always need explicit approval.

How many case studies does a small business need?

Start with one per main service, prioritised by the enquiries you receive most often. Three well chosen stories cover most of what prospects ask before they buy.

Where should case studies be published?

Give each one a page on your own site, linked from the relevant service page, then reuse extracts in proposals and email replies.

See also

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