PSS interview + Case interview

Hi Rholane,

Given that you’re already in the second and final round and have no prior case experience, the most important thing is to start practicing with a coach as soon as possible. With limited time, coached practice will help you get the right direction early, avoid building bad habits, and focus only on what matters for the interview.

In the next one to two days before booking a coach, keep things very lightweight. Read a short overview of McKinsey case interview structure, familiarize yourself with basic concepts like issue trees and hypothesis driven thinking, and watch one or two example interviewer led cases, Victor Cheng’s online practice videos are a good reference to understand flow and expectations. Avoid deep drilling or trying to memorize frameworks at this stage.

After that, moving to a coach is the most efficient step. A coach can help you structure cases correctly from day one, practice under realistic conditions, and prioritize what will make the biggest difference in the limited time you have.

Happy to draft a plan on how to make sure you’re ready by then and put yourself in the best position to get the job.

Best,
Evelina

First, congrats on making it to the final round. That's not easy.

Now, zero case experience with a final round coming up is tight, but not hopeless. Here's what I'd suggest.

Understand what cases actually test. They want to see structured thinking, logical problem-solving, and clear communication. For a data scientist role, they'll likely lean toward data-heavy or analytical cases rather than pure business strategy.

Learn the basics fast. Watch a few case videos online to see what good looks like. Spend a couple hours understanding common structures: profitability, market sizing, investment decisions. You don't need to master them all. Just get familiar with the format.

Focus on your strengths. As a data scientist, you already think analytically. Cases are just structured problem-solving out loud. Lean into that. When you see data or numbers, that's your comfort zone. Use it.

Practice out loud. Don't just think through cases in your head. Talk through them. Record yourself. The hardest part for beginners is thinking and speaking at the same time. Get used to that feeling.

Do a few practice cases. Even 5-10 cases will make a difference. Find a friend, use online case partners, or do them solo with case books. Something is better than nothing.

For data scientist cases specifically, expect to interpret data, draw insights from charts, and explain your reasoning. They may also test how you'd approach a problem using data. Think about how you'd structure an analysis, what data you'd need, and what conclusions you'd draw.

On meeting a coach, even one or two sessions could help if you have time. They can spot your weak points quickly and give you targeted feedback. But if time is too short, focus on self-practice and getting reps in.

You've made it this far. They already see potential in you. Now just show them you can think clearly under pressure.

Good luck.

That means the partners will be casing you and you'd need to pass the DS-version of cases even if you don't need one as good as the generalists must. 

agree with EM above

Hey Rholane, 

First of all: don’t panic. This situation is stressful, but it’s manageable, even with limited case experience.

A few steps I’d recommend:

1) Clarify scope with recruiting.
Since you’re applying for a Data Scientist / Expert role, reach out to the recruiting team and ask whether they can narrow down the case type (e.g., data-heavy, analytics-driven, expert-style case vs. classic generalist case). This can significantly focus your preparation.

2) Buy time if you can.
If the interview date isn’t fixed yet or if there’s flexibility, I’d reach out to recruiting asap to see whether you can push it back slightly. You don't want to go into the interview unprepared!

3) Practice as much as possible, but efficiently.
With limited time, prioritize quality over quantity:

• Targeted sessions with a coach can be very effective to quickly identify gaps, set a clear approach, and avoid practicing the wrong things.
• In parallel, practice with peers as much as you can to build basic structure, confidence, and flow.

4) Focus on making the most of the next few days.
You won’t master everything, and that’s okay. Focus on clear structuring, logical thinking, and communicating your reasoning, especially leveraging your data background where relevant.

Fingers crossed it all works out - let me know if you'd like to talk through how to make best use of your time :) 

Rholane, 

Go on youtube and search 'mckinsey consulting interview case'. Click one of them just so you get a sense of what to expect. 

In parallel, reach out to your recruiter to confirm whether for the DS role you'll be doing DS-focused cases or generic / any industry cases. That will help you prioritise the prep. 

Try a few cases from the case library here on PrepLounge. 

Then do get a coach. Why? Because instead of spending days / weeks / months trying to find your way, you'll get a clear idea of where you are now (innate strengths and areas of development), what is the gap to interview readiness, and what is the most effective way to close that gap. It's a bit like getting a swim coach at the start of your career, not one week before your swimming competition. 

If you have any specific questions, don't hesitate to reach out. 

Best,
Cristian

This is a fantastic place to be—congratulations on making it to the final round. Your urgency is warranted, but you need to strategically pivot your prep away from what generalist candidates do.

For a Data Scientist role at McKinsey, your final round "case interview" is highly unlikely to be the classic, framework-driven profitability analysis you see online. The firm already knows you have the technical chops; the final round is designed to test how you communicate those chops to a Partner. The PSS component (Problem Solving Skills, often a behavioral or scenario question) and the case work together to assess your structured thinking. Your case will likely involve assessing the technical feasibility of a business objective or diagnosing why a model failed to deliver expected value.

Since time is critical, forget memorizing classic frameworks like the 3 Cs or Porter’s Five Forces. Instead, spend the next 48 hours mastering communication clarity and organization. When faced with a problem, structure your response immediately into three main buckets:

1. Clarify: State all your initial assumptions and define the scope of the problem ("Before I analyze, I need to confirm we are optimizing for X metric within Y timeframe.")

2. Hypothesize/Structure: Lay out 2-3 structured pathways to solve the problem (e.g., "To approach this data integration issue, I would first check data integrity, second analyze ETL process efficiency, and third look at schema consistency.")

3. Synthesize: End with a clear recommendation that links the technical solution directly back to the business objective.

Your goal is to demonstrate that you can break down a complex, ambiguous problem into clean, manageable steps for an interviewer who might not be technical themselves. This discipline is what they are looking for, not a perfect model design.

All the best!

Hi Rholane :)

first of all congrats, making it to final round is already a strong signal. for data scientist roles at McKinsey the case is not a classic MBA style case, it is much more about structured thinking, problem decomposition and how you reason with data, so zero traditional case prep is not a deal breaker at all. the best use of your time now is to practice structuring simple business problems out loud, be very clear on assumptions, and get comfortable walking someone through your logic step by step rather than jumping to answers. also refresh basic business concepts like revenue, cost, profit and how analytics can inform decisions, but keep it high level. once you have that baseline, a coach can help you polish, but right now focus on clarity and structure over frameworks. happy to help you sanity check your approach anytime if you want.

best,
Alessa :)

Hi Rholane,

You should try to push back your interview date as much as possible by communicating with HR that you need more time to better prepare for the interviews. They generally are quite understanding with this.

You should read up on the basics of how a case interview is done, and try 2-3 yourself. Then, I highly recommend you have an initial session with a coach so the coach can direct you on which areas you should focus on most. Give it another 1-3 weeks preparation before meeting up with the coach again to track your progress.