Prepping for interview with EY-Parthenon

Question

Hi all,

I am prepping for an interview with EY-Parthenon in the second week of October. To date, I have completed 11 cases, 2 of which were during live case interviews with another top-tier consulting firm in March this year. That was really great learning. I have read Case in Point, and I am halfway through the Crafting Cases course "Case Interview Fundamentals", which I find really helpful.

By now, I have a decent understanding of the anatomy of a case and the skills required. I have identified two areas I definitely need to improve:

1. Structuring

2. Case interview-style math

My goal is first to complete the Crafting Cases fundamental course. Then I aim to do a mix of a skill-driven approach (i.e. structuring drills, math drills) and live case practice.

However, I really doubt which resources to use. I don't want to use too many, preferably just one for each (one for skills and one for practice cases). I am considering using Rockblocks for the skill-driven part and either PrepLounge or CaseCoach for practicing cases. I have also considered using Victor Cheng's math program for math drilling.

Your input is most appreciated to help me lay the best foundation for preparing.

Many thanks in advance!

Answer 1

Hi Joachim,

Congrats for getting the interview! The other good news is that you have sufficient time to prepare, with the right approach

I think you touched on the main components, but here are additional thoughts

Nail the case studies:
1) Learn some basic frameworks and understand when/how they work (MECE).
2) Practice as much as possible (I would recommend 5 days a week, even if it's just 30min). And of course, make sure to get some feedback after every mock case study. So either a coach or peers with strong experience in case studies
3) Practice "exotic" cases/frameworks, so that you are not taken by surprise during the actual interview
Aim for Zero-defect when calculating
1) Do regular math drills, quick mental math, etc
2) Learn the tips to avoid making mistakes - this is something I can help with
Do not overlook the "fit"
1) Prepare and rehearse your story: e.g. why do you want to go into consulting, and why EY-Parthenon?
2) Prepare some answers to basic questions using the STAR framework, leveraging your past experience

These are the main points to help you prepare. And more than happy to set up a free intro call to discuss this further or help you practice case studies!

Good luck!

Oussama

Answer 2

Hi there,

You’re approaching this in a smart and structured way — narrowing down resources rather than drowning in too many. A couple of thoughts:

1. Structuring practice

Crafting Cases is already excellent for learning how to break down problems and think MECE.
Rockblocks is a good complement if you want quick, repeated drills to sharpen structuring muscles. That’s all you need here — you don’t need a second major resource for structuring.

2. Math practice

Case-style math is best practiced in case context, but drills can accelerate fluency.
Victor Cheng’s math program can feel a bit mechanical and dated. I’d suggest using CaseCoach math drills or Rockblocks’ math packs instead. They’re closer to the style you’ll face at EY-Parthenon and focus on business intuition, not just raw calculations.

3. Live case practice

PrepLounge = huge variety of partners but quality is mixed. Best if you want volume and exposure to different styles.

4. Suggested streamlined plan

Finish Crafting Cases Fundamentals (your base).
Use Rockblocks for daily structuring + math drills (10–15 minutes/day).
PrepLounge practise with coaches.
Mix in 2–3 live practices per week once you’re done with fundamentals; focus the rest of your time on drilling weak spots.

Feel free to reach out!

Best,

Evelina

Answer 3

Hey Joachim :)

Your plan is solid from my experience! Finish Crafting Cases first, then add focused drills. Rockblocks is great for structuring, and CaseCoach is better than PrepLounge for well-designed practice cases. For math, you don’t need Victor Cheng’s program .. just daily mental math drills with business-style numbers (e.g. Rocketblocks math, free GMAT/consulting math apps, or simple timed drills). Combine this with regular live practice, since that’s where structuring and math come together under pressure.

best, Alessa :)

Answer 4

Hi there.

Former EY-Parthenon Principal here. I have some retired real cases that I use in my sessions, feel free to reach out if you want a targeted coaching session.

A few notes:

Make sure you are well prepared for market sizing / estimates
Math should be practiced mostly in the context of these estimates (and break even problems, etc.)
More important than the number is how the number impacts the recommendation
Please throw away the "Case in Point" type of frameworks. That type of "bucket" approach is not adequate for current consulting interviews. You need to be objective driven (questions / topics stem directly from the problem you want to solve) and avoid "generic" buckets or memorized frameworks at all cost.