Case Interview Playbook

Master the structured problem-solving interview used by McKinsey, BCG, Bain & every top strategy firm — phases, frameworks, and AI-powered practice.

The case interview tests one thing: can you solve complex business problems in real time? This playbook teaches you the universal flow, the four case types, and lets you practice with instant feedback.

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The Golden Rule of Case Interviews

Don’t memorise frameworks — learn to think. Every case is unique. The best candidates adapt their approach to the specific problem, not force-fit a template they learned from a prep book.

01

Phases of a Case Interview

Every case follows the same universal flow. Master each phase and you’ll perform well regardless of the case type.

1Prompt
2Recap
3Clarify
4Structure
5Analysis
6Conclusion
Phase 1

Receiving the Prompt

The interviewer presents you with a business problem. Listen carefully — take notes on key facts, numbers, and the specific question being asked. Don’t start thinking about your structure yet; just absorb the information.

Pro tip: Write down the exact question the interviewer asks. You’d be surprised how many candidates solve a different problem than the one they were given.
Phase 2

Recap & Paraphrase

Before doing anything else, paraphrase the prompt back to the interviewer in your own words. This is not about repeating it word-for-word — it’s about demonstrating that you truly understood the situation and the question.

Good Recap Example

“So if I understand correctly, our client is a mid-size European retailer that has seen a 15% decline in profits over the past two years, and they’ve hired us to identify what’s driving this decline and recommend actions to reverse it. Is that right?”

This simple step accomplishes three things: confirms you understood correctly, gives you a moment to organise your thoughts, and shows the interviewer you’re a careful, structured thinker.

Phase 3

Clarifying Questions

This is one of the most critical phases and where many candidates lose points. The right clarifying questions show the interviewer you think before you act. Ask questions in these categories:

1

Identify the Task

Ask: “What exactly is the client asking us to do?” This helps you classify the case into one of the four types (Go/No-Go, Diagnostic, Brainstorming, or Estimation). Sometimes the prompt is deliberately vague — this question cuts through that ambiguity.

2

Client Objective

Ask: “What is the client’s ultimate objective?” Is it to maximise profits? Grow market share? Reduce costs? The objective shapes your entire approach and determines what “success” looks like.

3

Focus Metric

Identify the key metric you need to improve, reverse, or reach. This is essential for Go/No-Go and Diagnostic cases. What specific number will tell us whether we’ve succeeded? Profit margin? Revenue growth? Customer retention rate?

4

Target Level & Timeline

Ask: “What profit level are we aiming for? What revenues are we targeting? What’s the timeline?” Knowing the target quantifies the gap between where the client is and where they need to be, which directly informs your analysis.

5

Business Model

Understand: What does the business do? Where does it operate? How does it make money? You don’t need a deep dive — just enough context to avoid making recommendations that don’t fit the business reality.

6

Clarification of Terms

If any term is vague, clarify it immediately. “Market share” — in volume or revenue? “Improve happiness” — how are we measuring happiness? “Costs have increased” — total costs or unit costs? 20 seconds of clarification saves 3 minutes of wasted work.

⚠️ Common Mistake: Skipping clarifying questions to “save time.” If you solve the wrong problem or use the wrong metric, everything downstream is wrong. The 60 seconds you invest here will be the most valuable of the entire case.
Phase 4

Structuring Your Approach

Once clarifying questions are done, you transition to structuring:

A

Ask for Time

“I’d like to take a minute to structure my thoughts before I walk you through my approach.” This is completely expected and professional. Take 60–90 seconds.

B

Build Your Structure

Write down your approach: the key areas you’ll investigate, the logical flow, the metrics you’ll need. This is your roadmap for the entire case.

C

Verbalise It — Top-Down & Prescriptive

This is crucial and often undervalued. When you present your structure, be prescriptive, not descriptive.

❌ Descriptive (Weak)

“So we have revenues and costs. Revenues come from volume and price. Costs have fixed and variable…”

Just reading your notes out loud. No direction, no ownership.

✅ Prescriptive (Strong)

“To answer whether our client should enter this market, I’d evaluate three conditions. First, does it make financial sense — I’ll build a profitability model. Second, does our client have the capabilities to execute. Third, what risks could derail us. Let me start with the financial analysis.”

Clear direction, shows ownership and leadership.

Remember: The interviewer is evaluating whether they would trust you in front of a real client. A consultant who says “we have revenues and costs” sounds passive. A consultant who says “I recommend we start by analysing X because Y” sounds like a leader.
Phase 5

Analysis: Exhibits, Math & Brainstorming

The analysis phase is where you execute your structure. It typically involves three types of work:

📊 Analysing Exhibits (Charts & Data)

1
Ask for time to review.

“May I take a moment to go through this exhibit?” Read the title, axes, units, legend. Clarify anything unclear before saying a word about the data.

2
Share insights, not descriptions.

Don’t say “Revenue went from 100 to 120.” Say “Revenue grew 20%, which is below the market average of 35%, suggesting we’re losing relative ground.” The interviewer can read the chart — they want to know what you see in it.

3
Propose next steps proactively.

“Based on this, I’d like to drill deeper into the cost structure to understand what’s driving the margin decline. Specifically, I hypothesise that…” Always be leading the case forward.

🔢 Doing Math

1
Structure before you calculate.

Even if the math looks easy, take a few seconds to lay out your approach: “To compute the profit impact, I’ll first calculate revenues by multiplying units by price, then subtract total costs which are fixed plus variable. Let me walk through this.”

2
Verbalise as you go.

Talk through each step so the interviewer can follow and catch any errors early. This also shows your thought process clearly.

3
Avoid sloppy mistakes.

Double-check your units, decimal places, and order of magnitude. A mistake of 10x kills your credibility. If you’re unsure, do a quick sanity check: “That gives us €2M in profit — for a company this size, that feels reasonable.”

💡 Mini Brainstorming within a Case

Sometimes mid-case the interviewer asks: “What ideas do you have for improving X?” or “What are the risks here?”

Key: Before brainstorming, clarify the question. “When you say improve customer retention, are we focused on reducing churn of existing subscribers or increasing repeat purchases from one-time buyers?” Those 20 seconds of clarification prevent 3 minutes of answering the wrong question. Then apply the same MECE structuring principles from the Brainstorming case type.
Phase 6

The Conclusion

The conclusion is your final impression. Structure it with this framework:

1

Restate the Question (Briefly)

“To answer the question of how our client can reverse the profit decline…” — just one sentence to ground the recommendation.

2

Give the Recommendation Directly

“…we would recommend focusing on three actions: renegotiating supplier contracts, launching the premium product line, and exiting the underperforming Southeast region.”

3

Supporting Facts

Back up each recommendation with the evidence you found during the case. “Supplier costs account for 60% of the margin decline, and we identified that competitor pricing is 20% lower from the same suppliers.”

4

Risks & Mitigation

Show maturity by acknowledging what could go wrong: “The main risk is that renegotiating supplier contracts could disrupt supply continuity. To mitigate this, we’d recommend identifying backup suppliers before beginning negotiations.”

5

Next Steps

“As next steps, I’d suggest a detailed supplier analysis in a follow-up project, and a pilot launch of the premium line in two test markets. Happy to continue this in our next meeting.”

This shows you understand how consulting engagements work — problems don’t get solved in one meeting, and suggesting follow-up work is exactly what a real consultant would do.

02

The 4 Case Types

Every consulting case falls into one of four types. Learn to recognise which you’re facing and apply the right methodology.

How to Recognise the Case Type

If the prompt asks…It’s a…Your goal
“Should we do X?” / “Yes or no?” / “Which option?”Go/No-GoEvaluate conditions → decide yes or no
“Why is X happening?” / “What’s causing the problem?”DiagnosticFind root cause → recommend fix
“How can we improve X?” / “What ideas do you have?”BrainstormingGenerate structured, MECE ideas
“How big is the market?” / “Estimate the number of Y”EstimationBuild a logical calculation

Type 1: Go/No-Go

Any decision that answers yes/no — “Should we launch X?”, “Should we acquire Y?”, “Should we enter market Z?”

Core Approach

Define 2–4 conditions that must be met to say “yes.” Then evaluate each condition systematically. The conditions are not a fixed template — you must define them based on the specific prompt and client objectives.

Typical Conditions (adapt to each case)

C1

Financial Sense

Does it make economic sense? The core formula:

Yearly Profit × Number of Years > Investment Cost

Break down Yearly Profit into Direct Effects (revenue minus operational costs) and Indirect Effects (synergies, cross-selling, cannibalisation). Always separate the one-time investment cost from ongoing operational costs — never mix them.

Tailor it: Don’t stop at generic “Revenue minus Costs.” A mobile app case should have “monthly active subscribers × average subscription price.” A logistics case should have “shipments per month × revenue per shipment.” Generic = memorised. Specific = thinking.
C2

Capabilities

Can the client actually do it? Check: people, infrastructure, technology, capital. It might make financial sense, but if the client can’t execute, it’s a no-go.

C3

Risks

Four categories to check systematically:

Business
Market shifts, competitor moves, changing demand
Operational
Internal bottlenecks, resource diversion, key talent loss
Strategic
Partner dependency, supplier reliability, joint-venture issues
Regulatory
New laws, policy changes, compliance requirements
Comparing Multiple Options

When the case presents choices (“Which of 3 markets should we enter?”), it’s still Go/No-Go. Build the same formula per objective, compare all options using identical metrics, and think top-down: start with the big number, then decompose.

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Type 2: Diagnostic

Identify the root cause of a problem — “Why have costs increased?”, “Why are sales declining?”

Two-Step Approach

Step 1: Analysis (find the root cause) → Step 2: Strategic Recommendations (propose solutions). Always clarify during the prompt: does the interviewer want just the root cause, or also a solution?

Step 1A: Quantitative Analysis — Isolate the numeric driver

Break the problem into its numerical components. Compare to a benchmark to see which component has moved.

Customer Service Costs (+30%)
# of Incidents ✓ Stable
Cost per Incident ↑ Increased
AI Support (cheap) — stable
Human Calls (expensive) — ↑ proportion increased

Keep drilling deeper on the branch that shows change until you isolate one or two specific numeric drivers.

Step 1B: Qualitative Analysis — Understand WHY

Now that you know what changed numerically, brainstorm possible reasons and investigate each until you find the real cause. Then present your hypothesis and ask the interviewer for data to confirm.

Step 2: Strategic Recommendations

Recommend actions that directly address the root cause. Not generic “improve customer service” — but specific solutions that flow logically from what you found.

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Type 3: Brainstorming

Generate structured ideas — “How can we increase revenues?”, “What can we do to reduce churn?”

Core Principle: Be MECE

Don’t list random ideas. Build a tree that is Mutually Exclusive and Collectively Exhaustive — every idea falls into exactly one category, and no category is missing.

Classic Example: “How can we increase revenues?”

Increase Revenue
With EXISTING Products
In Existing Markets
  • Increase Volume — new customer segments, sell more to current customers (frequency, upsell, cross-sell)
  • Increase Price — raise prices, shift product mix toward higher-margin items
In New Markets
  • Geographic expansion — new countries, regions, cities
  • New channels — online, wholesale, partnerships
With NEW Products
  • Adjacent products — accessories, add-ons, premium tiers
  • New categories — diversification into unrelated offerings
Methodology for any brainstorming question: (1) Find the highest-level MECE split. (2) Break each branch into specific, actionable ideas. (3) Tailor to the case — the revenue tree above is an example, not a template. A “reduce employee turnover” question needs a completely different tree built with the same MECE logic.
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Type 4: Estimation

Market sizing or calculating a missing data point — “How big is the market for Uber in Spain?”

1

Check if you need to estimate

Always ask: “Do we have this data, or should I estimate it?” Sometimes the interviewer has the number ready.

2

Clarify scope

What metric? What geography? What time period? What definitions? (Market size = revenue or volume?)

3

Structure your approach

Do not start calculating yet. Choose top-down (start big, filter down) or bottom-up (start from one unit, build up). Present your approach to the interviewer for approval before you start the math.

4

Get interviewer approval

“I’d start by taking Spain’s population, then segment by urban population, age group, and smartphone penetration — does this approach work?”

5

Execute calculations

Use anchor points (known benchmarks). Segment numbers for precision. Explain the rationale behind each assumption. Round generously.

6

Sanity check & implications

Does the number make sense? (“That implies 1 in 5 people use this — does that feel right?”) Flag the most uncertain assumptions and state what would change the result most.

⬇️ Top-Down

Start from the largest number, filter down:

Population → % urban → % target age → % smartphone users → % adoption rate

⬆️ Bottom-Up

Start from one small unit, build up:

Avg. cars/day → % enter shop → % buy snack → avg. spend → × 365 days

03

Cross-Cutting Principles

These apply across all four case types and every phase of the interview.

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Don’t Memorise Frameworks

Learn the 4 case types and adapt. Rigid frameworks break when the case doesn’t fit the template. Interviewers can instantly tell when you’re reciting.

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Lead, Don’t Ask

“I recommend we analyse X because Y” — never “What should I do now?” You are leading a project; the interviewer is your partner, not your manager.

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Be Coachable

The interviewer’s redirects are help, not traps. Follow them gracefully — they’re testing whether you’d be good to work with on a real project.

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Clarify First, Always

If you solve the wrong problem, nothing else matters. Invest time in understanding before structuring. 60 seconds of clarification saves the entire case.

Tailor Everything

The more specific your structure is to the actual business, the stronger you look. Generic = memorised. Specific = genuine thinking.

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Think Like a Consultant

Suggest follow-up projects, mention next meetings, propose risk mitigation. Show you understand how consulting firms actually operate.

04

Ready to Practice?

Put the theory into action with our interactive case simulator.

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Interactive Case Interview Simulator

Simulate a real case interview from start to finish. Get a random case prompt, then work through each phase — recap, clarifying questions, structure, exhibit analysis, math, and conclusion — with AI-powered feedback at every step. The next phase only unlocks once you’ve completed the current one, just like in a real interview.

Launch Case Simulator →

Guía de Entrevistas de Caso

Domina la entrevista de resolución de problemas estructurada utilizada por McKinsey, BCG, Bain y todas las firmas top — fases, frameworks y práctica con IA.

La entrevista de caso evalúa una cosa: ¿puedes resolver problemas de negocio complejos en tiempo real? Esta guía te enseña el flujo universal, los cuatro tipos de caso y te permite practicar con feedback instantáneo.

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La Regla de Oro de las Entrevistas de Caso

No memorices frameworks — aprende a pensar. Cada caso es único. Los mejores candidatos adaptan su enfoque al problema específico, no fuerzan una plantilla que aprendieron de un libro.

01

Fases de una Entrevista de Caso

Todos los casos siguen el mismo flujo universal. Domina cada fase y rendirás bien independientemente del tipo de caso.

1Prompt
2Recap
3Clarificar
4Estructurar
5Análisis
6Conclusión
Fase 1

Recibir el Prompt

El entrevistador te presenta un problema de negocio. Escucha con atención — toma notas de los hechos clave, números y la pregunta específica. No empieces a pensar en tu estructura todavía; solo absorbe la información.

Fase 2

Recap y Paráfrasis

Antes de hacer nada, parafrasea el prompt al entrevistador con tus propias palabras. Demuestra que entendiste la situación y la pregunta. Esto confirma tu comprensión, te da un momento para organizar tus pensamientos y muestra que eres un pensador estructurado.

Fase 3

Preguntas de Clarificación

Fase crítica donde muchos candidatos pierden puntos. Pregunta sobre:

1

Identificar la Tarea

¿Qué nos está pidiendo exactamente el cliente? Esto te ayuda a clasificar el caso en uno de los 4 tipos.

2

Objetivo del Cliente

¿Maximizar beneficios? ¿Crecer cuota de mercado? ¿Reducir costes? El objetivo define todo tu enfoque.

3

Métrica Clave

¿Qué número específico debemos mejorar, revertir o alcanzar? Margen de beneficio, crecimiento de ingresos, retención…

4

Nivel Objetivo y Plazo

¿Qué nivel de beneficio buscamos? ¿Qué ingresos objetivo? ¿En qué plazo?

5

Modelo de Negocio

¿Qué hace la empresa? ¿Dónde opera? ¿Cómo gana dinero? Contexto básico antes de cualquier recomendación.

6

Aclaración de Términos

Si algo es ambiguo, aclara inmediatamente. “Cuota de mercado” — ¿en volumen o ingresos? 20 segundos de clarificación ahorran 3 minutos de trabajo perdido.

Fase 4

Estructurar el Enfoque

Pide tiempo (“Me gustaría tomar un minuto para estructurar mis ideas”), construye tu estructura, y luego verbalízala de forma prescriptiva y top-down: “Para responder si debemos entrar en este mercado, evaluaría tres condiciones. Primero…” No descriptiva: “Tenemos ingresos y costes…”

Fase 5

Análisis: Exhibits, Matemáticas y Brainstorming

Exhibits: Pide tiempo para revisar, aclara lo que no entiendas, comparte insights (no descripciones), y propone próximos pasos de forma proactiva.

Matemáticas: Estructura antes de calcular, verbaliza cada paso, evita errores descuidados, haz sanity checks.

Mini-brainstorming: Siempre clarifica la pregunta antes de generar ideas. Aplica los mismos principios MECE del tipo Brainstorming.

Fase 6

La Conclusión

Estructura tu conclusión en 5 partes: (1) Repite brevemente la pregunta, (2) Da la recomendación directamente, (3) Apoya con hechos del caso, (4) Menciona riesgos y cómo mitigarlos, (5) Propone próximos pasos (“Encantado de continuar en nuestra próxima reunión”).

02

Los 4 Tipos de Caso

Cada caso cae en uno de cuatro tipos. Aprende a reconocer cuál enfrentas y aplica la metodología correspondiente.

Si el prompt pregunta…Es un…Tu objetivo
“¿Debemos hacer X?” / “¿Sí o no?”Go/No-GoEvaluar condiciones → decidir sí o no
“¿Por qué está pasando X?” / “¿Qué causa el problema?”DiagnósticoEncontrar causa raíz → recomendar solución
“¿Cómo podemos mejorar X?” / “¿Qué ideas tienes?”BrainstormingGenerar ideas estructuradas y MECE
“¿Cuál es el tamaño del mercado?” / “Estima el número de Y”EstimaciónConstruir un cálculo lógico

Tipo 1: Go/No-Go

Cualquier decisión sí/no. Define 2–4 condiciones que deben cumplirse para decir “sí” y evalúa cada una: (1) Sentido financiero, (2) Capacidades, (3) Riesgos (negocio, operacional, estratégico, regulatorio).

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Tipo 2: Diagnóstico

Identificar la causa raíz. Paso 1A: Análisis cuantitativo (aislar el driver numérico). Paso 1B: Análisis cualitativo (entender POR QUÉ). Paso 2: Recomendaciones estratégicas que aborden directamente la causa.

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Tipo 3: Brainstorming

Generar ideas estructuradas. Ser MECE: encontrar el split de primer nivel que cubra todo, desglosar cada rama en acciones concretas, adaptar al caso específico.

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Tipo 4: Estimación

6 pasos: (1) Comprobar si necesitas estimar, (2) Clarificar alcance, (3) Estructurar enfoque (top-down o bottom-up), (4) Aprobación del entrevistador, (5) Ejecutar cálculos, (6) Sanity check e implicaciones.

03

Principios Transversales

Se aplican a los cuatro tipos de caso y a todas las fases de la entrevista.

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No Memorices Frameworks

Aprende los 4 tipos y adapta. Los frameworks rígidos fallan cuando el caso no encaja en la plantilla.

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Lidera, No Preguntes

“Recomiendo analizar X porque Y” — nunca “¿Qué debería hacer ahora?”

🤝

Sé Coachable

Las redirecciones del entrevistador son ayuda, no trampas. Síguelas con elegancia.

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Clarifica Primero, Siempre

Si resuelves el problema equivocado, nada más importa.

Adapta Todo

Cuanto más específica sea tu estructura al negocio real, más fuerte parecerás.

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Piensa Como Consultor

Sugiere proyectos de seguimiento, menciona próximas reuniones, propone mitigación de riesgos.

04

¿Listo para Practicar?

Pon la teoría en acción con nuestro simulador interactivo de casos.

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Simulador Interactivo de Entrevistas de Caso

Simula una entrevista de caso real de principio a fin. Recibe un prompt aleatorio y trabaja cada fase — recap, preguntas de clarificación, estructura, análisis de exhibits, matemáticas y conclusión — con feedback de IA en cada paso.

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