Turn one client win into a case study in a day

What a case study is (and what it isn't)

A case study is a short, factual account of one client's problem, what you did about it, and what changed as a result. It's written for a prospect who has the same problem and wants evidence that you can solve it. Its job is to make your claims believable.

It isn't a testimonial. A testimonial is the client's opinion of working with you; a case study shows the work and the outcome, and may include a testimonial as one part.

It isn't a portfolio piece either. A portfolio shows what the work looked like. A case study explains why you made the decisions you did and what they achieved, which is what a buyer comparing agencies needs to know.

And it doesn't need to be long or designed. Four hundred to seven hundred words on a plain web page, with real numbers and an approved quote, does the job. Design can come later, if ever. The case studies that help most are the ones that exist, are easy to link to, and match a prospect's situation.

Before you start: pick the right win

Pick a project where the client's problem is one your ideal prospects also have, where you can show a before and after (even a small one), and where the client is likely to agree to be named. A small, relevant win beats a big, unusual one.

Morning: get permission and the facts

Send the permission email first

Subject: Could we share the [project] results?

Hi [name],

We're really pleased with how [project] went, especially
[specific result]. We'd like to write a short case study about it
for our website.

It would cover the challenge, what we did together and the results.
We'll send you the draft before anything goes live, and you can
change or remove anything.

Two quick questions:
1. Are you happy for us to name [company], or would you prefer
   we keep it anonymous ("a regional dental group")?
2. Would you be up for a one- or two-sentence quote about working
   with us? Happy to draft one for you to edit.

Thanks either way,
[your name]

Offering to draft the quote makes it easy; the client edits rather than writes. Always send the final version for approval, and never publish a quote they haven't approved in writing. Check your client agreement before you send this: if it has a confidentiality clause, make sure it allows you to name the client or share results.

Gather the facts

While you wait, pull together the original brief or proposal, your starting metrics and the latest ones, the key dates, and the two or three non-obvious decisions that made the difference. Write each number down with its source and date range.

Midday: write it with this structure

Aim for 400–700 words in five sections:

Section	What goes in it	Length
1. Headline	The result, stated plainly ("How [client] went from posting twice a month to three times a week without adding staff")	One line
2. Client and problem	Who they are, what wasn't working, why it mattered then. Use their own words from early calls if you have them	Two short paragraphs
3. What you did	Three to five steps in order, focused on decisions rather than tasks	150–250 words
4. Results	Numbers with time frames and sources, or a concrete description of the change	100–150 words
5. Quote and next step	The approved client quote, then one line inviting readers with the same problem to get in touch	Two or three lines

In the results, write numbers like this: "Between March and August, newsletter sign-ups from social went from [X] to [Y] a month (from their email platform)." If the result isn't a number, be concrete: "The marketing manager now spends one hour a week on social instead of a day." Don't claim credit for results you didn't cause.

Afternoon: review, approve, publish

1. Read it aloud. Cut every sentence that's about you rather than the client's problem.
2. Send it to the client for approval with a specific deadline: "Could you approve or send changes by Thursday?"
3. While you wait, prepare where it will go.

Where to publish it

Where	How to use it
Your website	Its own page with a clear URL (/work/client-name). Everything else links here.
Proposals	Link the most relevant case study in every proposal for a similar prospect.
LinkedIn	Tell the story in your own words: the problem, one decision, the result. Tag the client if they agree.
Directory profiles and review sites	Add it wherever your agency is listed, if the site allows portfolio links or work samples.
Sales emails	One sentence and a link: "We solved something similar for [client], here's how."

Steps you can take today

1. List your three best client wins from the past year and pick the most relevant one.
2. Send the permission email above.
3. Pull the before and after numbers, with dates and sources.
4. Write a first draft using the five-part structure, aiming for 400–700 words.
5. Create a /work page on your website if you don't have one.
6. Add a link to the finished case study in your proposal template.

FAQ

How long should an agency case study be?

Four hundred to seven hundred words is enough for most case studies. That covers the problem, what you did and the results, without asking a busy prospect to read a report.

How do I ask a client for permission to write a case study?

Email them before you write anything, explain what the case study will cover, and promise they'll approve the draft before it goes live. Offer an anonymous version and offer to draft their quote, which makes saying yes easier.

What if my client doesn't want to be named?

Publish it anonymously with a clear description, such as "a regional dental group." An anonymous case study with real numbers is still far more convincing than no case study.

What results should I include in a case study?

Include the before and after numbers that matter to the client's goal, with the time frame and where the numbers came from. If the result isn't measurable, describe the concrete change in how the client works.

Where should I publish case studies?

Put each one on its own page on your website, then link to it from proposals, LinkedIn posts, sales emails and any directory profiles that allow work samples. Proposals are usually where a case study does the most work.

Do I need a designer to make a case study?

No. A plain web page with a clear headline, short sections and real numbers works well, and it can be published the same day. You can add design later if it ever becomes worth it.

How often should an agency publish case studies?

Aim for one whenever a project produces a clear result that matches the clients you want more of. A small library of relevant case studies is more useful than one polished showpiece.