How to Write a Case Study (Template & Examples)

A case study is a short, structured account of how a specific customer, patient, or organization went from a problem to a measurable result. In business, it’s used to prove a product or service works by showing one real outcome instead of making a general claim. This guide covers the five-part format, a step-by-step process, a fill-in template, and a worked example.

If you’re building the internal document a case study is often based on, see how to write an executive summary for how to compress the same facts into a one-page brief instead.

Case study format

Almost every business case study follows the same five parts, in this order:

1. Headline — the result, in one line (“How [Client] cut onboarding time by 40%”).
2. Introduction — who the client is and the context before the work started.
3. The challenge — the one specific problem they needed solved.
4. The solution — what was actually done, in enough detail to be credible.
5. The results — the measurable outcome, ideally with a number and a quote.

Skip any section that doesn’t earn its place. A case study is not required to be long — a tight 500 words that nails all five parts beats 1,500 words that pad the introduction.

How to write a case study

1. Choose a specific subject. Pick one customer, project, or event with a clear before-and-after, not your best client in general. A vague subject produces a vague case study.
2. Gather the facts before you draft. Collect the numbers, the timeline, and a direct quote from the person involved. Case studies fail when they’re written from memory instead of notes or a transcript.
3. Draft the five sections in order. Write the challenge and results first — they’re usually the easiest to state factually — then fill in the introduction and solution around them.
4. Cut for clarity. Short sentences, one idea per paragraph, and bullet points for anything with more than two items. A case study that reads like a brochure loses the “this is real” feeling that makes it work.

Case study examples

This is a condensed case study example, invented to show the format without reprinting a real company’s story:

How a 12-person agency cut client onboarding from three weeks to five days

Riverside Design, a 12-person branding agency, was losing new clients to a slow start: onboarding took three weeks of back-and-forth emails before any work began.

The challenge: New clients had to fill out four separate intake forms before the team could start, and half never completed all four.

The solution: Riverside replaced the four forms with one intake call, recorded and summarized into a single brief the same day.

The results: Onboarding time dropped from three weeks to five days, and intake completion rose from 52% to 94%. “We stopped losing clients before we’d even started,” said the agency’s founder.

Notice the headline states the number, the challenge is one sentence, and the quote does the emotional work instead of the prose trying to.

Case study template

Use this as a fill-in structure. The word counts are a starting point, not a rule — cut anything that isn’t doing work.

Headline: [Client] achieved [specific result] by [method], in one line.

Introduction (1–2 sentences): Who the client is, what they do, and the situation before you got involved.

The challenge (1–3 sentences): The one problem that mattered most. Not a list of everything that was wrong.

The solution (1–2 short paragraphs): What was done, specifically enough that a reader could picture it.

The results (2–4 sentences): The number that changed, plus a direct quote if you have one.

Case study vs. case study analysis

Everything above describes a business case study — a success story used for marketing or sales. If you were assigned a case study in school or at work to analyze rather than write, that’s a different task: a case study analysis. Instead of telling a success story, you’re given an existing situation, asked to identify the key problem, and expected to recommend or evaluate a solution using evidence from the case.

The four common types you’ll see referenced are business/marketing (the format above), academic or research (an analysis of a documented situation, often for a class), medical or clinical (a patient case report, following its own citation format), and instructional or training (a scenario used to teach a decision-making process). All four share the challenge-and-outcome shape; they differ in whether you’re telling the story or analyzing someone else’s.

Writing a case study about yourself — your own project, career decision, or personal outcome — is fine for a personal portfolio or a class assignment. Use the same five-part shape and be as specific about the “before” as you would about anyone else’s story.

Common mistakes

• Choosing a vague subject. “Our client saw great results” isn’t a case study; a subject you can name and a number you can cite is.
• Skipping the quote. A case study with no direct quote from the client reads like marketing copy, even when every fact is true.
• Padding the introduction. Readers want the challenge and result fast. If the setup runs longer than the challenge and solution combined, cut it.
• Burying the number. The result belongs in the headline, not the last sentence.

Turn interview notes into a case study draft

Most case studies start as raw material: a recorded client call, a project retro doc, or a thread of support tickets. Turning that into the challenge and results sections is a summarization job before it’s a writing job. Paste the transcript or notes into our free AI text summarizer to pull out the key facts and quotes in seconds, then drop them into the template above and shape them into your own sentences.

Frequently asked questions

What is the format of a case study? Five parts, in order: a headline stating the result, an introduction to the client, the challenge, the solution, and the results. Most case studies run 500–1,500 words.

What is a good example of a case study? One that names a specific subject, states one clear problem, and ends with a number you can point to — not a general description of “great service.”

Can I write a case study on myself? Yes. Use the same five-part format with yourself as the subject — a specific project or decision, not your career in general.

How long should a case study be? Most run 500 to 1,500 words, or one to two pages. Length depends on the format (a one-page sales sheet vs. a detailed report), not on how much happened.

What are the four types of case studies? Business/marketing (a success story), academic/research (an analysis of a documented situation), medical/clinical (a patient case report), and instructional (a scenario used for teaching). This guide covers the first in depth and the differences between them above.