Good afternoon everyone,
I have been invited to the McKinsey Data Science I interviewing round which has a TEI+PEI along with a pair programming session. I don't know how to fully prepare for this one because all I have is internships and a hackathon. Can anyone give me any pointers on how best to prep for these 2 sessions? If a former data scientist can help that would be amazing.
Hey Rholane:)
you can prepare exactly like for the generalist interviews, just make your stories more technical when helpful. They mainly check how you work in teams, handle challenges, and drive impact, not how many projects you have. Even internship or hackathon examples are totally fine if you show clear ownership and thought process. For the pair-programming part they focus on how you communicate, structure your approach, and debug calmly. It is much more about collaboration than perfect code, so just practice talking while coding.
If you want, I can walk you through how to structure your stories or how a pair-programming round usually feels.
best, Alessa :)
This is a great place to be, and you've hit on the central challenge of specialist recruiting at MBB: the expectation for deep technical rigor combined with the standard behavioral screening. Don't worry about only having internships and hackathons; that is exactly the type of experience they anticipate for entry-level specialist roles. The key is how you frame those experiences.
For the TEI (Technical Experience Interview), McKinsey isn't looking for proof you’ve managed a $100M project; they are looking for rigor in your decision-making. You must treat every past project, even a hackathon, as a full-cycle business problem. Use the STAR method, but focus the "Result" less on the final accuracy score and more on the trade-offs you made: Why did you choose that specific model over another? What critical data leakage issue did you solve? How did you ensure the solution delivered value to the user/client, not just good metrics? This interview is designed to ensure you think like an applied Data Scientist, not just a coder.
The PEI (Personal Experience Interview) remains the gatekeeper, just as it is for the generalist role. Your technical competence gets you the interview, but your ability to exhibit leadership, entrepreneurial drive, and personal impact determines whether you get the offer. You must develop 3-4 deep, polished stories (drawing from those internships or even academic group projects) that squarely hit those three dimensions. Be ruthless in sticking to the structure and focusing on your specific actions and impact.
Finally, the Pair Programming session is not a competitive coding exam. The primary goal is to assess your collaboration style and ability to handle ambiguity under pressure. You must communicate every step of your thought process—literally narrate your plan, the edge cases you're worried about, and why you are choosing one Python library over another. Talk out loud constantly. If you get stuck, explain where you are stuck and propose a pivot to the interviewer. Showing strong, structured thinking and collaborative problem-solving is far more valuable than optimizing the last two lines of code.
Hope this helps you focus your prep! All the best.
Rholane,
Congrats on the invite!
Discuss with the recruiter to check first of all if they will be testing data science knowledge through a case or only through stories.
Then make sure that you also develop stories that show you having a significant impact on a data science project.
Re how to build the stories, I developed a course specifically for this that you might find useful:
Best,
Cristian
Thanks.