McKinsey PEI – Depth of Follow-ups & Best Way to Structure Answers?

Question

Hi all - I’m preparing for McKinsey interviews and had the following Qs on PEI:

1. What type of follow-ups did you receive?

Mostly open-ended probes (e.g., “What were you thinking?” “Why that approach?” “What would you do differently?”)
Or more specific factual/detail questions (e.g., “How many team members were involved?” “Exactly what did you say?”)?
Or a mix of both?

2. In terms of answering style, what's the best approach?

STAR if its an approach question? Or short direct answer?

And whats the best way to prep for follow-ups?

Answer 1

1 - both

2 - STAR, but be flexible. If it's a short follow-up, no need to give a big, proper STAR, but if there are more and more questions in that area, it's worth taking a step back and presenting the situation properly.

If you're working on the PEI, I would recommend this material I've built specifically for it:

• • Video Course: Master the McKinsey PEI

If you'd like to know more about it, don't hesitate to drop me a line.

Best,
Cristian

Answer 2

hey there :)

I would say you should expect a mix of follow ups, but they tend to go much deeper than most candidates anticipate. You will get both reflective questions like what were you thinking, why did you choose that approach, what would you do differently, and very specific detail questions like exactly what did you say, how did the other person react, how many stakeholders were involved. The goal is to test authenticity and depth, so they drill into your personal actions and decision making logic.

In terms of structure, start with a clear and concise STAR style narrative to set the scene, but keep it tight and spend most of the time on your actions and reasoning. For follow ups, do not repeat the full story. Answer directly and specifically, then add a short reflection if relevant. They care much more about your personal contribution and thought process than about the context.

The best way to prep is to take two or three strong stories per dimension and practice being pushed on them for ten to fifteen minutes straight. Ask a friend to challenge every statement with why, how exactly, what did you think, what was the risk, what was the alternative. If you can defend your story calmly and consistently under pressure, you are ready.

If you want, feel free to share your stories and I can stress test them with you.

best,
Alessa :)