Live case
Built from your questions, out loud, from the start.
- Data
- Given when you ask
- Output
- A spoken recommendation
The written case interview, worked from packet to slides
In a written case interview you get a packet of information, a set time to read and analyze it alone, and then either present your recommendation or hand in what you wrote. BCG's Amsterdam office lists a 2.5-hour written case in its final round. Bain lists a take-home written assignment, likely with three days to finish, as one interview type that depends on the role, though its consulting process typically lists a digital assessment and case interviews. We build Soreno, an AI voice interview practice app. The math in a written case is the same as in a live one, so warm up with our free case math drills with no sign-up, then present the worked case below out loud.
Updated
- What you get
- A packet and a clock
- Read, analyze, then present or hand in
- BCG Amsterdam
- 2.5 hours, final round
- Beside two 60‑minute cases
- Bain
- Take-home, about 3 days
- For some roles, sometimes presented
- Worked example
- 40 stores, 4 slides
- Invented by us, every number shown
What is a written case interview?
The Isenberg Undergraduate Consulting Group at UMass Amherst describes it this way: you're handed a deck of information and given a set time to read, analyze and form an answer, the interviewer may leave the room, and at the end you either present your conclusion or turn in your writing. A live case gives you a few sentences and builds from your questions. In our experience, a written case gives you everything at once, much of it noise, and tests whether you can find the answer and show it on a few slides.
Written case
Everything at once, alone, then presented or handed in.
- Data
- A packet, some of it noise
- Output
- Slides or a memo, then questions
Worked example: Harbor Coffee (ours)5 steps
Harbor Coffee, an invented chain of 40 coffee shops, has seen profit fall for two years. The CEO's note on the first page of your packet asks: why, and what should we do in the next 12 months? This case and every number in it are invented by Soreno for practice.
Read the question first
Why, and what in 12 months
Two questions, so two parts to the answer. Write both at the top of your notes before you open the exhibits, and skip anything that answers neither. In our packet, a customer survey about music and seating is the noise.
Find the numbers
Profit fell from $4.99 million to $4.51 million
Downtown: 12 stores at $1.2 million each with a margin of 18%, so $2.59 million. Suburban: 20 stores at $900,000 each with a margin of 12%, so $2.16 million. Mall: 8 stores at $600,000 each with a margin of minus 5%, so a loss of $240,000. Total store profit is $4.51 million, down $480,000 from two years ago.
Find the driver
Mall stores explain 100% of the fall
Downtown and suburban stores haven't moved. Mall store revenue fell from $750,000 to $600,000 a store, and their margin went from 4% to minus 5%. That swing, $480,000, is the whole drop. Each mall store now loses $30,000 a year.
Size the options
Close 5 at lease end: $150,000 a year
5 of the 8 mall leases end within 12 months, so closing those costs nothing to exit and stops $150,000 a year of losses. The other 3 would cost $90,000 each to leave early, which the $30,000 a year each store loses pays back in 3 years. Closing all 8 would lift yearly store profit to $4.75 million, after a one-time $270,000 to leave the other 3 early. That is still short of the $4.99 million of two years ago, because the mall stores used to make money.
Write the slides
Answer on slide 1, proof on 2 and 3, risks on 4
Slide 1: "Close the 5 mall stores whose leases end in the next 12 months, and decide on the other 3 by spring." Slide 2: "Mall stores explain all of the $480,000 profit fall." Slide 3: "Closing 5 at lease end saves $150,000 a year at no exit cost." Slide 4: "Risks: lost mall customers may not move to nearby stores. Next: test it with sales at the nearest suburban stores after the first closure."
Which firms say they use a written caseFrom their own pages
Only two of the firms we checked describe a written case on their own careers pages. Formats differ by office and role, so read your invitation.
BCG Amsterdam
A 2.5-hour written case in the final round
BCG's Netherlands page lists the final round as four interviews: a 45-minute personality-based interview with a recruiter, two case interviews (listed as 60 minutes) and a written case of 2.5 hours. The first round is two case interviews, also listed as 60 minutes. It says interviews are hybrid, some virtual and some at the Amsterdam office.
BCG: application process in the NetherlandsBain
A take-home written assignment, for some roles
Bain's interviewing page says interviews are customized to the role. One type is a written assignment: a take-home challenge related to the role, which you'll likely have three days to complete, and in some cases you present the result. For consulting roles, the same page says the process typically consists of a digital assessment and then case interviews.
Bain: interviewingEveryone else
Ask your recruiter
Guides online give page counts, calculator rules and slide templates for specific firms. We found none of that on the firms' own pages, so ask your recruiter what you'll get: how long the packet is, whether you can write on it or use a calculator, and whether you write slides by hand or on a laptop.
Pushback to expect after you present (ours)3 questions
Questions we'd ask on the Harbor Coffee case, with the answer we'd want.
On the cause
Isn't this just a bad two years for malls?
"Maybe, and that's the point. Even if mall traffic recovers to two years ago, those stores made 4% against 12% in the suburbs. I'd rather put the money where it earns more."
On the data
Exhibit 6 says mall stores have the highest customer ratings. Why close them?
"Ratings matter if they turn into visits. Revenue per mall store is down 20%, so the people who rate them highly aren't coming often enough to cover the rent."
On the plan
What would make you change your mind?
"If sales at the nearest suburban stores don't pick up after the first closures, the mall stores were bringing in customers we can't replace. Then I'd keep the other 3 and renegotiate rent instead."
From UMass Isenberg Undergraduate Consulting Group: Mastering the Case Interview, BCG: application process in the Netherlands and Bain: interviewing.
What interviewers look for in a written case
The Isenberg guide's four steps are read the question first, find the numbers, manage your time and formulate a well thought out presentation. In our experience, these are where marks are won or lost.
An answer on the first slide
Lead with what the client should do and why, in one sentence. The slides after it are the proof.
Signal over noise
A packet is built with exhibits that don't matter. Say which ones you set aside and why, if asked.
Numbers you can defend
Show the calculation behind each headline number, in units, so the interviewer can check it in seconds.
Calm under pushback
Expect the interviewer to point at an exhibit that seems to contradict you. Answer it, then say what would change your mind.
Time plans for a written case (ours)
Our split for a 60-minute and a 150-minute written case. Adjust to the time on your invitation, but decide the split before you start reading.
60 min: 0 to 10 / 150 min: 0 to 20
Question, then skim
Read the question and any conclusion or CEO note first, then skim every exhibit's title. The Isenberg guide says a conclusion, if there is one, gives you a reference point for the rest.
60 min: 10 to 35 / 150 min: 20 to 90
Analyze the exhibits that matter
Work only the exhibits that answer the question. Write each insight as a full sentence as you find it: those sentences become your slide titles.
60 min: 35 to 50 / 150 min: 90 to 130
Write the slides
Three to five slides: the answer, two or three pieces of proof and risks with next steps. One message per slide, written as its title.
60 min: 50 to 60 / 150 min: 130 to 150
Check and rehearse
Recheck every number on the slides, then say the first slide out loud once. If you run out of time, a clear answer on slide 1 beats a full deck with none.
From UMass Isenberg: Mastering the Case Interview.
The minute splits are ours. No firm we checked publishes a time plan.
12 prompts to practice as written cases
Soreno's own prompts. For each, give yourself 60 minutes, build the numbers you would expect in a packet and write three to five slides. Under each is what a strong deck does.
Profit and cost
Find where the money went.
A grocery chain's profits are down 20% this year. Why, and what should it do?
Splits the drop by store group or product line on slide 2 and leads with the one that explains most of it. Practice it, see a model answer
A retailer needs to cut costs by 10% without hurting sales. Where should it look?
Ranks cost lines by size and by how much each could fall, then shows the total reaches 10% on one slide. Practice it, see a model answer
An airline is carrying more passengers but making less money. What's going on?
Puts revenue and cost per passenger side by side over time and names the one that moved. Practice it, see a model answer
A software company is growing fast but losing more money each year. Should it slow down?
Separates the cost of growth from the cost of running the business, then answers the question in one line. Practice it, see a model answer
Growth and entry
Decide where to go next.
A furniture retailer wants to start selling online. Should it, and how?
Sizes the online market it could reach, shows the cost of delivery and returns, then recommends a first step that can be tested. Practice it, see a model answer
An e-bike maker is weighing entry into the US market. What do you recommend?
One slide on market size, one on what it takes to win, one on the go or no-go with the main risk. Practice it, see a model answer
A gym chain wants to double its revenue in five years. How should it get there?
Shows the options adding up to the target in one chart, so the reader sees the gap each one closes. Practice it, see a model answer
A coffee chain is thinking about entering India. Should it?
Leads with the answer and the one number that drives it, such as how many stores it needs to break even. Practice it, see a model answer
Big decisions
Yes or no, with the numbers behind it.
One of your client's three divisions is losing money. Fix it, sell it or close it?
Compares the three options on cash over the next few years and names what else breaks if the division goes. Practice it, see a model answer
Should a manufacturer build a second factory?
Shows demand against capacity on one slide and payback on the next, with the demand risk on the last. Practice it, see a model answer
Should a company make a key component itself or keep buying it?
Compares cost per unit both ways at today's volume and at the volume where the answer flips. Practice it, see a model answer
You've finished the analysis and the CEO walks in. What do you tell them?
Says slide 1 out loud in under a minute: the answer, the two reasons, the main risk and the next step. Practice it, see a model answer
Common written case mistakes
The ones we see most when candidates present a written case in practice.
Reading every page before deciding anything
Read the question first, then go looking for what answers it. Packets are longer than the time you have on purpose.
Slide titles that describe instead of conclude
"Store profit by segment" tells the reader nothing. "Mall stores explain all of the profit fall" is the point.
No time left for the slides
Analysis expands to fill the clock. Stop at the time you set yourself and write.
A number with no working
If the interviewer can't see how you got it, they will ask, and you will spend the Q&A defending arithmetic.
Two answers instead of one
"It could be A or B" is not a recommendation. Pick one, then say what would change it.
Present your answer and take the pushback
Soreno's AI interviewer runs full cases out loud, hands you exhibits when you ask, pushes back on your recommendation and scores the session. Start your free week.
Questions people ask
What is a written case interview?
A case where you get a packet of information and a set time to read and analyze it on your own, then present your recommendation or hand in what you wrote. A live case, by contrast, gives you data only when you ask for it.
Which consulting firms use written case interviews?
On their own careers pages, BCG's Amsterdam office lists a 2.5-hour written case in its final round. Bain lists a take-home written assignment as one interview type that depends on the role, but doesn't say consulting candidates get it. Other firms and offices may use one too. Check your invitation or ask your recruiter.
How long is a written case interview?
It depends on the firm and office. BCG Amsterdam lists 2.5 hours. Bain says its take-home written assignment likely gives you three days. Your invitation should say.
How many slides should I make?
In our experience three to five: the answer, two or three slides of proof and one on risks and next steps. More slides usually means less time checking the numbers.
Can I use a calculator in a written case?
We found no firm page that says. Ask your recruiter, and practice the math by hand so it doesn't matter.
Is a written case harder than a live case?
It tests different things. There is less back and forth to steer you, so finding the question in the noise and managing your time matter more. The math and the recommendation are the same.
What is a case presentation interview?
A written case where you present your slides to the interviewer and take questions at the end. Bain says that in some cases you present the result of its take-home assignment.
How do I practice for a written case?
Take a case prompt, set a 60-minute timer, build the numbers you'd expect in a packet and write three to five slides. Then present slide 1 out loud and have someone push back on it.