3 Tips for Written Case Interview

Key Insights:

• Read The Questions Before The Data: Start with the prompt and the questions you must answer, build a structure, then go to the exhibits. That order keeps you out of "paralysis by analysis."
• Most Exhibits Are Not Equal: A written case pack mixes core data with background and noise. Pick the exhibits that answer the questions, and combine two exhibits when one alone can't give you the insight.
• The Deck Is The Answer: Interviewers score an executive summary that leads with the recommendation, 3 to 5 slides with action titles, and a next steps slide you can defend in Q&A.

---

A written case interview gives you a packet of data, a set of questions and a fixed amount of time to build a short slide deck, which you then present to an interviewer. This guide is for candidates who have been told a written case is coming, usually in a final round. You'll get the firms that use it, what happens on the day, what interviewers score, a 5-step method, a worked example with sample slides, and a prep plan.

If you already handle a live case interview well, you have most of the skills you need. The written case interview tests the same thinking. What changes is that you work alone, you pick the data yourself, and your answer has to live on a page.

Written Case Interview At A Glance:

What it is	A case you solve alone from a packet of exhibits, then present as a short deck
Who uses it	Some offices of Bain, BCG, PwC and Strategy&, Deloitte, Capital One and Advancy, most often in final rounds
Materials	About 15 to 40 pages of charts, tables and text
Prep time	About 1 to 2 hours in the office, or 24 to 72 hours for a take-home version
Deliverable	Usually 3 to 5 slides: executive summary, supporting slides and next steps
Presentation	A short pitch followed by Q&A, often 20 to 30 minutes in total

What Is A Written Case Interview?

A written case interview is a business case you solve on your own from a printed or digital pack of exhibits, then present as a few slides. Instead of asking the interviewer for data, you get all of it up front, often with more pages than you can use.

The skills are the same ones a live case tests: structure, prioritization, case math, synthesis and communication. The difference is the format. In a live case, the interviewer steers you toward the right data. In a written case interview, you have to find it, decide what to ignore, and make the "so what" clear on the page before anyone asks.

That's why firms use it. A written case shows how you'd work on a real team: someone hands you a data room and a question, and you come back with a few slides and a point of view.

Which Firms Use The Written Case Interview?

Several top firms use a written case interview in some offices, usually in the final round. The format depends on the firm, the office and the role, so treat the table below as a starting point and confirm the details with your recruiter.

Bain	Used by some offices, most often in the final round and for MBA candidates, and more often in Europe and Asia. You get a pack of about 20 to 30 slides and about 1 hour to review it and complete 3 to 5 partly built slides. No calculator. Then you present and answer questions.
BCG	Office dependent, usually in the second round (Chicago is one office known for it). About 40 pages of documents and about 2 hours to build 3 to 5 slides, starting with an executive summary. Calculator rules vary by office.
PwC and Strategy&	Some offices, usually in the final round. A document pack and about 60 minutes to build 3 to 5 slides, then 20 to 30 minutes to present plus Q&A. Some offices send a take-home case 24 to 48 hours ahead.
Deloitte (Monitor Deloitte)	Some offices and strategy roles. About 15 to 25 pages and 50 minutes to 2 hours to prepare, then a short presentation of about 10 to 15 minutes and Q&A.
Capital One	Some business analyst and strategy tracks include a written case on Power Day, the final round. Candidates describe a deck of about 20 slides with a problem statement and data, which they turn into a recommendation.
Advancy	Some offices, mostly in Europe, use a written case or a pre-read packet. You analyze it alone, then present and defend your conclusions.

Two notes. First, BCG's Casey chatbot is not a written case. It's an online case with a short recorded answer, and our BCG Online Case guide covers it. Second, you don't need a separate prep plan for each firm. One strong method works for all of them, and the steps below are that method.

What Happens On The Day Of A Written Case Interview?

On the day, a written case interview runs in five stages: you receive the pack, analyze it, build your slides, present, and answer questions. Most of your time goes to the middle three.

1. Receive The Pack: You get the prompt, the questions and the exhibits, on paper or on a laptop. Some firms give you blank slide templates. Others give you partly built slides to complete.
2. Analyze: You work alone. You read, structure, pick the exhibits that count, and run the math.
3. Build The Slides: You write 3 to 5 slides by hand or in PowerPoint. Each slide carries one message.
4. Present: You walk the interviewer, sometimes a partner, through your answer. Plan on 5 to 10 minutes for the pitch itself.
5. Q&A: The interviewer tests your logic, your numbers and your judgment. Expect pushback on your recommendation, the same way a client would push back.

Ask your recruiter four things before the day: how much time you'll have, whether you'll write by hand or in PowerPoint, whether a calculator or Excel is allowed, and how long the presentation runs.

What Do Interviewers Score In A Written Case Interview?

Interviewers score a written case interview on the same core skills as a live case, plus the quality of the slides and how well you defend them. Here's the rubric MC coaches use with candidates. Firms don't publish their scorecards, but these are the areas every debrief comes back to.

Structure	You framed the problem before the data and stayed hypothesis driven
Prioritization	You used the exhibits that answer the question and skipped the rest
Math	Your numbers are right, rounded sensibly, and tied to the question
Synthesis	Every number on a slide comes with its "so what"
Slide quality	Action titles, one message per slide, an executive summary first
Presence and Q&A	You lead with the answer, stay calm under pushback, and know your risks

For a closer look at how case performance gets graded, see our insider's look at the case scoring system.

How Do You Solve A Written Case Interview, Step By Step?

You solve a written case interview in five steps: read the questions first, structure the problem, triage the exhibits and run the math, build the deck, then present the answer first. The first three steps come from the method MC teaches in the video below. The last two cover the slides and the presentation, which is where many candidates lose points.

Step 1: Read The Questions Before The Data

Start by reading only the prompt and the questions you've been asked. Don't flip through the exhibits yet. If you start with 30 pages of charts, you'll spend your time on what's interesting instead of what's asked, which is the trap of "paralysis by analysis."

Write the core question at the top of your scratch paper in one sentence. Note the decision the client has to make and any target they've set, such as a profit goal or a deadline.

Step 2: Structure The Problem And Set A Hypothesis

Build a structure the same way you would in a verbal case. List the areas you need to test, the data you'd want for each one, and an early hypothesis. Our case interview structure guide and case interview frameworks guide show how to build a short issue tree that fits the problem.

For a "should we launch this" question, the tree might be three branches: Is the market attractive? Can we make money? Can we execute? Only once that structure is on paper do you move to the data.

Step 3: Triage The Exhibits And Run The Math

Now go through the pack and sort each exhibit against your structure. Mark each one as core, supporting or skip. Many packs include background pages, company history or data for a question you weren't asked. Skim those once and move on.

Look for exhibits that only make sense together. A survey that shows how many customers might buy, plus a plan that assumes a subscriber count, gives you one insight when you put them side by side: is the plan realistic? Combining one or two exhibits into a single insight is often the best slide in the deck.

Then run the math carefully. Write every step, round sensibly and sanity check each result against the market size or the company's revenue. If calculators aren't allowed, build speed with our case math drills and exhibit drills.

Step 4: Build The Deck

Build a deck of 3 to 5 slides that tells one story. Use this order:

1. Executive Summary: Your recommendation in the title, then 3 or 4 bullets with the reasons and the key numbers.
2. Supporting Slides: One slide per reason. Each has an action title, a full sentence that states the takeaway, and only the data that proves it.
3. Risks And Next Steps: What could make you wrong, and what the client should do next to find out.

An action title says what the data means. "Year 3 profit of $5.0M clears the target only if churn stays at 40%" is an action title. "Year 3 financials" is a label. Read only your titles in order: if they tell the full story, the deck works. This is the pyramid principle on paper.

Step 5: Present The Answer First And Handle Q&A

Open with your recommendation in one sentence, then walk through the reasons. Don't read your slides out loud. Point the interviewer to the one number on each slide that proves your point.

In Q&A, expect the interviewer to test your weakest assumption. Name your risks before they do. If they find a math error, own it, fix it out loud and say whether it changes your answer. A calm correction scores better than a defensive one.

What Does A Written Case Interview Example Look Like?

Here's a short written case interview example with four exhibits, the model analysis and three sample slides. Give yourself 45 minutes, work with pen and paper, and build your own slides before you read the answer.

The Prompt

Your client is Larkspur Coffee Co., a brand that sells bagged coffee through grocery stores. Larkspur has $200M in revenue and an 8% operating margin. Grocery chains are pushing on shelf prices, so the CEO is considering a direct-to-consumer coffee subscription that would launch in 2027. The board wants the subscription to add at least $5M in operating profit by Year 3 (2029).

Answer three questions:

1. Market: Is the coffee subscription market attractive?
2. Economics: How much operating profit would the subscription earn in Year 3?
3. Recommendation: Should Larkspur launch, and what are the risks and next steps?

Exhibit 1: U.S. Coffee Subscription Market

Market size, 2026	$1.5B
Expected annual growth, 2026 to 2029	10%
Share held by the top 3 players	45%
Average subscription price	$30 per month

Exhibit 2: Survey Of Larkspur Grocery Buyers

Households that buy Larkspur each year	4.0 million
"Very likely" to subscribe	10% of buyers
"Very likely" buyers who actually subscribe (past launches)	1 in 4
Subscribers who would stop buying Larkspur in grocery	60%, each shifting $150 per year of grocery sales
Larkspur contribution margin in grocery	30%

Exhibit 3: Subscription Unit Economics (Per Subscriber, Per Month)

Price (2 bags at $16)	$32
Coffee and packaging	$8
Shipping	$8
Payment and fulfillment	$2

Exhibit 4: Launch Plan

Active subscribers (Year 1, 2, 3)	30,000; 60,000; 100,000
Annual churn	40% of the prior year's subscribers
Cost to acquire a new subscriber	$80
Fixed costs (platform, team)	$4M per year

The Model Analysis

Market (Exhibit 1). The market grows from $1.5B to about $2.0B by 2029 ($1.5B x 1.1 x 1.1 x 1.1 = $1.9965B). The top 3 players hold less than half, so there's room for a new brand. The average price of $30 a month is close to Larkspur's planned $32, so the price looks realistic.

Is the subscriber plan realistic (Exhibits 2 and 4 together)? 4.0 million buyers x 10% "very likely" = 400,000 households. If 1 in 4 actually subscribe, that's 100,000 subscribers, which matches the Year 3 plan. The plan is aggressive but grounded in the survey. It also means Larkspur needs about 1.9% of the 2029 market (100,000 x $32 x 12 = $38.4M revenue, divided by $2.0B).

Year 3 operating profit (Exhibits 2, 3 and 4):

• Contribution: $32 minus $18 in variable costs = $14 per subscriber per month. 100,000 x $14 x 12 = $16.8M.
• Acquisition cost: New subscribers needed = growth (100,000 minus 60,000 = 40,000) plus churned subscribers (40% x 60,000 = 24,000) = 64,000. 64,000 x $80 = $5.12M.
• Fixed costs: $4.0M.
• Lost grocery profit: 60% x 100,000 = 60,000 shifting subscribers. Each shifts $150 x 30% = $45 of contribution. 60,000 x $45 = $2.7M.
• Year 3 operating profit: $16.8M minus $5.12M minus $4.0M minus $2.7M = $4.98M, or about $5.0M.

Sensitivity. The result sits right at the $5M target, so test the riskiest assumption. If churn is 50% instead of 40%, Larkspur needs 40,000 + 30,000 = 70,000 new subscribers, acquisition cost rises to $5.6M, and Year 3 profit falls to $4.5M. On the upside, each subscriber pays back the $80 acquisition cost in about 6 months ($80 / $14 = 5.7 months).

The "so what." The opportunity is real, but the business case only clears the bar if churn and conversion hold. That points to a pilot before a national launch, not a yes or no.

Three Sample Slides

Slide 1, Executive Summary. Action title: Launch a 6-month subscription pilot before committing to a national rollout

• The subscription earns about $5.0M in operating profit in Year 3, right at the board's $5M target
• The market is large and growing, about $2.0B by 2029, and Larkspur needs under 2% of it
• Profit depends on churn: at 50% churn instead of 40%, Year 3 profit falls to $4.5M
• Next step: a pilot in 2 metro areas to test conversion and churn before scaling

Slide 2, Supporting Slide. Action title: Year 3 profit of $5.0M clears the target only if churn stays at 40%

• Bridge from contribution to profit: $16.8M contribution, minus $5.1M acquisition, minus $4.0M fixed costs, minus $2.7M lost grocery profit = $5.0M
• Lost grocery profit is the hidden cost: 60% of subscribers already buy Larkspur in stores
• Churn at 50%: $4.5M, below target
• Payback per subscriber: about 6 months

Slide 3, Next Steps. Action title: A 6-month pilot answers the two questions that decide the rollout

• Test conversion: do at least 1 in 4 "very likely" buyers in the pilot cities subscribe?
• Test churn: does monthly churn stay at or below about 4% (40% a year)?
• Go if both hold; adjust price or delivery cost and retest if either misses
• Track grocery sales in pilot cities to measure the real shift from stores

Want the full exhibit pack and model deck? The full version of this written case interview example has more exhibits, including the distractor pages real packs include, plus a complete model deck with charts. Request the full pack by email and practice it under real time limits.

How Should You Split Your Time In A Written Case Interview?

Split your time so that at least a third goes to the slides and you finish with a few minutes to rehearse. Most candidates run out of time because they spend too long in the data. Use these splits as a starting point and adjust once you know your format.

60 minutes	5 read the questions, 10 structure and triage, 20 math, 20 slides, 5 rehearse
90 minutes	5 read the questions, 15 structure and triage, 30 math, 30 slides, 10 rehearse
2 hours	10 read the questions, 20 structure and triage, 40 math, 40 slides, 10 rehearse
Take-home (24 to 72 hours)	Day 1: questions, structure and analysis. Day 2: slides and two timed run-throughs. Cap your total effort at about one working day, because interviewers judge focus, not page count.

What Are The Most Common Written Case Interview Mistakes?

The most common written case interview mistakes are reading every exhibit before you know the question, running out of time for slides, and writing slides without a message. Watch for these:

• Starting With The Data: You lose 20 minutes on pages that don't answer the question.
• Using Every Exhibit: Some pages are there to test whether you can ignore them.
• Label Titles: "Market Overview" tells the reader nothing. Write the takeaway.
• Numbers Without A "So What": Every figure on a slide should support the recommendation.
• Burying The Answer: If your recommendation shows up on the last slide, the interviewer has to wait for it.
• No Risks Or Next Steps: A recommendation without them sounds untested.
• Unchecked Math: One wrong number on a slide can sink an otherwise strong deck.

How Do You Prepare For A Written Case Interview In 1 To 2 Weeks?

You prepare for a written case interview by doing full timed practice cases, building real slides, and presenting them out loud to someone who will push back. If you have a final round coming up, this 1 to 2 week plan works on top of your live case prep:

1. Days 1 To 3, Build The Habits: Practice the read, structure and triage steps on 3 or 4 exhibit-heavy cases from our case library. Drill math daily, without a calculator if your firm doesn't allow one.
2. Days 4 To 7, Full Timed Cases: Do 2 or 3 complete written cases under your real time limit. Build the slides in the format you'll use on the day: by hand or in PowerPoint.
3. Days 8 To 10, Present And Defend: Present each deck to a partner or coach and take 10 minutes of tough questions. Fix the weakest slide each time.
4. Days 11 To 14, Polish: Do one final timed case, review your action titles, and rest the day before.

Practice out loud. The presentation is part of the score, and it's the step candidates rehearse least. For a full schedule that covers live cases too, see our case prep plan, and for more examples, see our case interview examples.

Video: 3 Tips For The Written Case Interview

In this short video, Jenny Rae walks through the three steps behind MC's method: read only the prompt first, build a structure as if it were a verbal case, then pull the data into a storyline with an agenda, a key takeaway slide and a next steps slide.

How Do You Get Ready To Win Your Written Case Interview?

A written case interview can feel like a test you can't practice, but it's one of the most coachable rounds in the process. The method is fixed: questions first, structure next, the right exhibits, clean math, and a short deck that leads with the answer. Once you've done it under time a few times, the format works for you, because you get to shape the whole story before anyone asks a question.

If you want expert feedback on your slides and your delivery, MC's Black Belt program pairs you with former MBB consultants for 1:1 coaching on written cases, live cases and fit interviews.

Additional Resources:

• Case Interview: Complete Prep Guide
• Case Interview Structure
• Case Interview Examples
• Bain Case Interview
• BCG Case Interview
• BCG Online Case (Casey)
• Capital One Case Interview
• Advancy Case Interviews
• Case Interview Math
• Exhibit Drills

Written Case Interview FAQs