Most case studies on design and agency websites are a set of nice-looking screenshots followed by a claim about increased engagement. They're pleasant to look at and they persuade almost nobody, because the reader can't tell what was actually done or whether the result had anything to do with it. Here's what a case study needs to contain to be worth the effort of writing.
Start with the situation, not the solution
The reader is looking for themselves. They want to know whether you've handled a problem like theirs before. That means the most useful thing you can lead with is the state the client was in when they picked up the phone.
Be specific and be honest about it. The business had grown into three divisions and the website still described one. Enquiries were arriving from the wrong sort of customer. The booking system and the website disagreed about availability. These are recognisable situations, and recognition is what makes someone read on.
A case study that opens with the finished design is answering a question nobody asked yet.
Say what was actually decided
The interesting part of any project is the decisions, not the deliverables. Which audience got priority when they conflicted. What got cut and why. Where the client disagreed and how that resolved.
This is the part almost every case study leaves out, usually because it's the part that involves compromise. But compromise is what real projects are made of, and a reader who runs a business knows that perfectly well. A case study with no difficult decisions in it reads as either fiction or a very small job.
Naming a decision also demonstrates judgement, which is the actual thing being sold. Anyone can produce a nice-looking page. Knowing which page to make nice-looking is the harder skill.
Be careful with numbers
A figure with no baseline, no time period and no attribution is worse than no figure at all, because a sceptical reader will assume the worst about the parts you left out. Enquiries up 240% could mean four became fourteen over two years while the client also started running ads.
If you have a number, give it context. What it was before, what it was after, over what period, and what else changed during that time. If other things changed, say so. That honesty costs you very little and buys a lot of credibility.
And if you don't have measured results, which is common because plenty of clients don't share their numbers, say what you can substantiate instead. Describing the work accurately is more persuasive than a statistic the reader doesn't believe.
Show the work, including the unglamorous parts
Full-bleed screenshots of the homepage are the least informative images in most case studies. Show the content structure. Show the mobile version of the page that does the actual commercial work. Show the CMS the client's team uses every week.
For a buyer trying to assess whether you'd be good to work with, a screenshot of a well-organised editing interface is more reassuring than another hero shot. It suggests someone thought about the eighteen months after launch.
Captions matter more than people expect. A caption that explains why something is the way it is turns a picture into evidence.
Say who did what
If a specialist developer built it, say so. If the client wrote the copy, say so. If you inherited an existing design system, say that too. Overstating your contribution is the fastest way to lose the trust of anyone who might check.
This matters more in a small market. Vancouver is not so large that a prospective client can't ask around, and a case study that claims more than it should is a conversation you don't want happening without you.
Being precise about scope also helps the reader work out whether you'd suit their project, which is the whole point of the exercise.
A structure that works
Situation, decision, response, outcome, and what you'd tell someone considering something similar. Five sections, each doing one job, in an order that matches how a buyer actually assesses a supplier.
Length matters less than usefulness. A well-made case study can be six hundred words. What it can't be is six hundred words of adjectives.
Write the one you'd want to read if you were spending forty thousand dollars with a studio you'd never met. That's a surprisingly reliable editor.