Consulting Articles > Consulting Case Interviews > LEK Case Interview: Format, Process, and How to Prepare

If you're applying to LEK Consulting, acing the LEK case interview is essential to landing an offer. The process is structured, rigorous, and includes both oral and written case components, along with behavioral questions. Understanding what to expect and how to prepare can help you stand out from other candidates.

In this article, we will explore the LEK interview structure, types of cases, preparation strategies, and tips to help you succeed.

What is the structure of the LEK case interview and process?

LEK’s interview process typically includes two rounds, combining case interviews, behavioral questions, and a written case presentation. The first round is mostly oral and includes math- and logic-heavy cases, while the final round adds a 60-minute written case exercise that requires slide creation and presentation.

LEK’s interview process starts with a first round that includes two 30-minute case interviews. Each is led by a different interviewer and usually blends business problem-solving with a few fit or behavioral questions. One case often emphasizes quantitative analysis, while the other may focus more on qualitative reasoning or strategic thinking.

If you advance to the final round, you can expect:

• Two additional 30- to 40-minute case interviews (similar format as round one)
• One written case interview lasting 60 minutes, which involves analyzing a slide deck and presenting findings

Throughout the process, LEK interviewers assess your analytical rigor, communication skills, and how well you structure your thinking. While the cases are all candidate-led, they follow a clear format and give you space to ask questions, request data, and guide the conversation.

It’s also common for behavioral questions like “Why consulting?” or “Tell me about a time you faced conflict” to be embedded within or after the case. These are brief but important, so prepare for them alongside your case prep.

What types of cases does LEK typically ask?

LEK typically uses strategy-focused, candidate-led case interviews, often featuring market sizing, profitability, growth strategy, and market entry problems. Some cases are heavy on quantitative analysis, while others emphasize logical structuring and business judgment.

You’ll encounter classic consulting case types, but with a distinct LEK flavor: a sharp focus on data interpretation, number-driven logic, and realistic business scenarios. Common categories include:

• Market sizing: Often standalone or embedded in a larger business problem. These test your ability to estimate demand using logical assumptions and arithmetic.
• Profitability analysis: You’ll be asked to identify declining profits or recommend ways to improve margins, requiring clear frameworks and numerical analysis.
• Growth strategy: These cases assess your strategic thinking, such as entering new markets, launching products, or expanding capacity.
• Market entry: You might evaluate whether a company should enter a new geography or industry, often involving competitor analysis and feasibility.
• Operational improvement: Occasionally, LEK tests how you would enhance processes, cut costs, or streamline a business unit.

The cases tend to be realistic, data-heavy, and framed in a way that mimics actual LEK project work. You’ll often need to synthesize both qualitative insights and quantitative findings to reach a clear recommendation. Frameworks help, but flexibility is key, especially when interpreting charts or evaluating tradeoffs.

How should you approach a candidate-led case at LEK?

To succeed in a candidate-led case at LEK, you need to take structured ownership of the discussion by actively driving the analysis, asking logical follow-up questions, and proposing next steps. LEK expects you to lead the case from start to finish using a clear, hypothesis-driven approach.

Begin by carefully listening to the case prompt and restating the objective to confirm alignment with the interviewer. Clarify any ambiguous details before diving into structuring. Then, lay out a tailored framework that breaks down the problem into manageable components-this shows that you can think logically and comprehensively.

Once your framework is approved or acknowledged, transition into hypothesis testing. Propose a direction based on initial facts, and use the data provided to either validate or refine your thinking. Communicate clearly as you analyze charts or perform mental math. Don’t just give answers-explain what the numbers mean and why they matter.

Throughout the interview, demonstrate initiative by:

• Asking thoughtful questions that reveal gaps in the case
• Using a top-down reasoning style to drive decisions
• Updating your hypothesis as new data emerges
• Keeping your analysis business-focused, not just technical

When you reach the end, synthesize your findings into a concise recommendation, supported by your analysis. If time allows, briefly mention potential risks or next steps.

How do you solve a market sizing question effectively?

To solve a market sizing question effectively in an LEK interview, break the problem into logical steps, use clear assumptions, and explain your reasoning at every stage. LEK looks for structured thinking, numerical accuracy, and clarity-not just a correct final number.

Start by clarifying the objective of the sizing exercise. Are you estimating annual revenue, number of users, or units sold? Then choose your approach:

• Top-down: Begin with a broad population or total market and narrow it down through relevant filters.
• Bottom-up: Start with one unit or transaction and scale it based on frequency, geography, or other relevant variables.

Make reasonable, transparent assumptions and round numbers for simplicity. State each step of your logic clearly as you move through the calculation. For example:

• If sizing the bottled water market in a city:
    → Estimate population
    → Assume daily consumption per person
    → Multiply by frequency and price

Accuracy is less important than logical consistency and clarity. If you need to pivot (e.g. shift from volume to revenue), explain why and adjust your structure accordingly.

Finally, sense-check your result. Is the number plausible? If it feels too high or low, say so and refine as needed. This shows good judgment.

What are the key evaluation criteria for LEK interviewers?

LEK interviewers evaluate candidates on five core areas: analytical rigor, structured thinking, communication, business judgment, and cultural fit. Each case is an opportunity to demonstrate how you think, not just what you conclude.

First, your analytical skills will be tested through mental math, data interpretation, and logical reasoning. Expect charts, tables, and numerical exhibits, especially in final rounds. Accuracy matters-but so does how clearly you explain your approach.

Structured thinking is another major focus. Interviewers want to see how you break down ambiguous problems. Strong frameworks, clearly defined objectives, and a logical order of operations all signal strong structuring.

Communication plays a critical role throughout the case. LEK values candidates who can synthesize complex ideas into simple, business-oriented explanations. This includes how you ask questions, summarize findings, and deliver your recommendation.

Business judgment is assessed through your assumptions, prioritization, and decision-making. Are you thinking like a consultant? Can you spot what matters most and avoid overanalyzing irrelevant details?

Finally, cultural fit is subtly assessed during interactions. Being coachable, personable, and intellectually curious makes a strong impression. Even if your answer isn’t perfect, showing confidence, collaboration, and resilience matters.

How should you prepare for the LEK written case interview?

To prepare for the LEK written case interview, practice analyzing large data sets, building slide headlines, and presenting structured recommendations under time pressure. The format tests your ability to extract insights quickly and communicate them visually and verbally.

The written case usually gives you 60 minutes to review a dense slide packet (often 40-50 pages), select key data, create a concise deck (usually 8-10 slides), and present your findings. Unlike traditional interviews, you won’t be asked verbal questions during the case-your slides and delivery must speak for themselves.

Here’s how to get ready:

• Practice scanning for insights: You won’t have time to read every slide. Instead, skim quickly and flag pages with actionable data, trends, or strategic implications.
• Use a framework: Before diving into slides, anchor your thinking with a basic framework (e.g. market, customer, financials) to structure your analysis.
• Write strong slide headlines: Each slide should have a clear takeaway, not just a description. Think of headlines as mini conclusions, not labels.
• Craft a logical story: Your slides should follow a narrative that builds to a recommendation. This usually starts with context, then analysis, then conclusion.
• Rehearse your verbal delivery: At the end, you’ll present your findings. Practice summarizing complex data in 1 to 2 sentences and supporting it with selected charts.

LEK interviewers are looking for clarity, logic, and professionalism-not perfect formatting. Use your time wisely and make sure every slide contributes to your recommendation.

What behavioral or fit questions should you expect within LEK interviews?

LEK interviews typically include behavioral or fit questions such as “Why consulting?”, “Why LEK?”, and “Tell me about a time you led a team.” These questions often appear at the beginning or end of a case and are used to assess your motivation, interpersonal skills, and cultural fit.

While they may feel brief compared to the case portion, your answers play a crucial role in the overall evaluation. LEK values candidates who are thoughtful, self-aware, and collaborative. To prepare effectively, use a structured approach like the STAR method (Situation, Task, Action, Result) to frame your answers.

Common behavioral questions at LEK include:

• Why do you want to work at LEK?: Focus on specific qualities that attract you, such as project diversity, global reach, or the firm's focus on strategy. Mention conversations with current consultants if applicable.
• Why consulting?: Highlight your interest in solving complex business problems, fast-paced learning, and meaningful client impact.
• Walk me through your resume: Summarize your background with an emphasis on leadership, problem-solving, and results that show readiness for consulting.
• Tell me about a time you handled conflict or failure: Show emotional intelligence, resilience, and how you grew from the experience.
• Describe a time you worked in a team or led one: Emphasize collaboration, initiative, and communication.

Make your answers authentic and concise. You’re not just demonstrating past behavior-you’re showing how you think, adapt, and interact in high-stakes environments.

How can you effectively practice and improve your performance?

To improve your performance for the LEK case interview, focus on deliberate practice: run mock interviews, build business intuition, refine mental math, and get feedback. Consistency and structured improvement are key to becoming confident and case-ready.

Start by working through realistic case prompts with peers or coaches. Simulate full interviews, not just isolated drills. After each session, review what went well and what needs refinement-especially your structuring, hypothesis testing, and synthesis.

You can also strengthen your preparation by:

• Practicing mental math daily: Prioritize speed and accuracy with percentages, ratios, break-evens, and multipliers.
• Reading business news and case studies: This builds your commercial awareness and helps you recognize real-world patterns in unfamiliar cases.
• Studying frameworks-but adapting them: Avoid memorization. Instead, focus on tailoring structures to each case’s unique objective.
• Reviewing your past cases: Keep a log of case types, what stumped you, and your revised approaches. Reflection accelerates growth.
• Simulating written cases: Practice summarizing slide decks and crafting slide headlines under timed conditions.

Lastly, don’t ignore behavioral prep. Record your answers to common fit questions and listen for clarity, tone, and authenticity. Strong case skills must be matched with strong communication.

Final Thoughts on Succeeding in the LEK Case Interview

The LEK case interview is a rigorous yet rewarding process that tests how you think, communicate, and solve real-world business problems. By understanding the structure, practicing case types like market sizing and profitability, and preparing thoroughly for both written and behavioral components, you’ll be well-positioned to stand out. Focus on clarity, structure, and consistency-because at LEK, how you work through the case matters just as much as the final recommendation.

Frequently Asked Questions

Q: What is the LEK final round interview?
A: The LEK final round interview focuses on advanced candidate-led case interviews and may include a timed written case exercise. It is designed to test higher-level problem-solving, data analysis, and presentation skills, as well as cultural fit.

Q: What is L.E.K. Consulting famous for?
A: L.E.K. Consulting is famous for its expertise in strategy consulting, data-driven market sizing, and sector-specific business case frameworks, particularly in life sciences, healthcare, and private equity.

Q: Does L.E.K. Consulting pay well?
A: Yes, L.E.K. Consulting generally offers competitive salaries and performance bonuses, especially for top performers who excel in case interviews and deliver strong client impact.

Q: What is the LEK SHL test?
A: The LEK SHL test is a psychometric and aptitude assessment used to evaluate numerical reasoning, verbal reasoning, and problem-solving ability before advancing to the case interview stage.

Q: What is the job hierarchy of LEK?
A: The job hierarchy at L.E.K. Consulting typically progresses from Associate to Consultant, Manager, and Principal, culminating in the Partner level. Each role increases responsibility for case leadership and client relationships.