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Fluctuations in casing performance - is this normal?

I have been practicing case maths since mid-2023 to break into consulting. Practice has been quite consistent (i.e. an hour a day on university months, 5 hours a day during uni breaks). For context, i was terrible when I first started, it took me around 30 minutes for even the simplest math questions !

While performance has greatly improved over this period, I can't help but feel dumb sometimes. For example, at times when I practice, I tend to answer all questions wrongly which is demotivating. One that has been persistent for some time is structuring accuracy. Where even with a checklist, I still tend to make mistakes (e.g. when it comes to incrementals, I take the ENTIRE business revenues, and not just revenues associated with an investment)

Is this normal? Any tips to overcome this ? Thank you!

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Kacper
Coach
22 hrs ago
Engagement Manager | Mock interview | Problem Structuring | MECEness | Fit Q&A | Winning CV | +20 min FREE

Hi there!

First of all, thanks for sharing this question - it happens more often than you may think!

I remember my own case a few years ago, where I had completed over 100 cases and was prepared for the toughest one (after already doing two rounds of BCG casing). However, while practicing a relatively easy case, I made a silly mistake that even surprised my case partner. I was so sure I understood the nature of the case that my focus slipped.

My lessons learned from that experience are:

  1. Too little space for breaks/reflection: Doing case after case every day can be stressful and put you into "autopilot" mode. Give yourself some space (i.e. day-off from cases) and do a 5-minute wrap-up after each case (to avoid making the same mistake twice).
     
  2. Work out some "rituals" while cracking cases: Almost every professional in sports has their own "rituals" to subconsciously cope with pressure (e.g., Rafa Nadal’s face-touching routine before serving). You can apply the same idea to case-solving. These "rituals" can help you stay on track even when you're experiencing a significant stress spike.
     
  3. Structure and paraphrase: Often, my coachees make the same mistakes - either not confirming assumptions or not paraphrasing the prompt of the case. I believe this may be the single most important factor you can work on to avoid mistakes in the future.

Let me know if the examples above make sense to you. I’d be happy to support you in working on these areas and help facilitate your journey into the consulting world! 

Florian
Coach
8 hrs ago
1400 5-star reviews across platforms | 600+ offers | Highest-rated case book on Amazon | Uni lecturer in US, Asia, EU

Hi there,

What you are describing is very common!

  • The key reason why candidates fail their case interviews and don't improve with practice is because they never learn the right approach and techniques to begin with. They might go through 30-40 cases, just repeating the same mistakes over and over again. There is often no strong baseline. This means that some cases go well, others don't.

  • Make sure you understand and learn the basics for each part of the case (structuring, charts, math), which is

    • A replicable step-by-step for each part of the case interview

    • The right thinking techniques around the individual parts (e.g., what's a framework, what is evaluated, how can I ensure I think about it the correct way, what are some shortcuts to get to the answer quickly, etc.)

    • Simple communication templates to help you communicate your insights as well as ask for data in the right way to drive the case forward

  • There are several approaches you can take, such as hiring a skilled coach, reading the right materials, or enrolling in relevant courses. For example, my book provides direct guidance tailored to modern case interviews. It covers all the essential points mentioned here, and more, while also offering a detailed preparation plan. You can find it on Amazon
  • Avoid generic advice and framework memorization approaches. This will only hurt your performance and waste a ton of time (why -> check out the first post here: https://www.preplounge.com/en/consulting-forum/how-goodrelevant-is-the-case-in-point-book-for-case-prep-1984)

  • Once you have that baseline it's time to practice and internalize the skills to create the right profile, polishing your strengths and lifting your weaknesses to a robust-enough level

  • Practice drills alone (structure, chart, math) and practice full cases with other excellent candidates that know the right habits and approach. It is crucial that you are practicing with really good peers, otherwise, it's a waste of time. Practicing drills on your own is a huge effectivity and efficiency booster since you can go over many more questions in a shorter amount of time compared to practicing with peers. Do both in parallel! You want to spend your time where it is most useful, e.g., if you struggle with math focus on math drills, etc.
  • Focus on quality over quantity. Doing 50+ cases does not mean much if you are not applying the right habits to score high and do a detailed debrief after every case to improve. You want to move from bad to good for your weaknesses and good to great for your strengths --> use the feedback from your previous experience and tailor your prep accordingly

  • Consider booking at least an initial coaching session to get a detailed and objective evaluation of your performance + learn the right habits for every case regardless of context and framework + get a tailored preparation plan out of the session that will set you up for an effective and efficient prep.

  • Don't forget the fit interview part. Prepare answers for all the typical fit questions and stories (3-5 hours) and rehearse them a couple of times (5 hours)

All the best,

Florian

Mariana
Coach
4 hrs ago
You CAN make it! | xMckinsey | 1.5h session | +200 sessions |Free 20-Minute Call

Hello there,

Totally normal. I went through the same thing. I was slow at math, made silly mistakes, even after months of practice. What helped me was doing more practice (it helped me identify patterns) and paying close attention to what was actually improving. Sometimes we’re so focused on the 10 percent that goes wrong that we forget the 90 percent that used to be a struggle and now flows!

Something that shifted things for me was doing two kinds of reviews after each session. First, I’d ask myself what went well and why. That helped me build confidence and identify what to keep doing, as the lack of it sometimes put us in a bad spiral (at least, that was my case). Then I’d look at what went wrong and break it down, not just the surface error, but the pattern underneath. Was I rushing? Skipping a logic check? Misreading what a term really meant?

Also, the days when everything goes wrong don’t cancel out your progress. I had those days too and they used to throw me off, but when I started tracking wins, even small ones, it gave me a more balanced view. One bad session doesn’t undo weeks of improvement.

You’re already doing the hard part, showing up and practicing consistently, 1h a day for 2.5 years is something very impressive. Keep going!

If you want a second pair of experienced eyes on your approach or just a professional to help you spot the patterns and fill this gap, happy to chat!

Best,

Mari

Alessa
Coach
2 hrs ago
xMcKinsey & Company | xBCG | +200 individual & group coachings | feel free to schedule a 15 min intro call for free

hey! 

Absolutely normal — casing progress isn’t linear, and everyone experiences ups and downs, especially with structure and math. The fact that you’ve come this far already is a huge win. For structuring, try slowing down just a bit to sanity-check your logic before diving in — especially on concepts like incrementals. Don’t let off-days shake your confidence; you’re on the right track!

Alessa

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