I understand the desire to ask this question (peace of mind), but think about how little worrying/thinking about this matters!

Nothing we say will change how you prep/perform...no matter what you're going to (and should) try your best.

The real answer is: You don't have to be better to get in, but even if you are perfect you may not get it!

It depends on office demand, interviewer-candidate dynamic, what types of errors are made, how frequently, etc.

You can "ace the case" and not get in because you just didn't seem like someone they'd want to work with. You can make a couple mistake and get rave reviews because you took in feedback super well, were insightful, and were a pleasure to case.

It honestly depends.

In terms of your specific question though...yes you can make an arithmetic error or two. Yes you can miss a sub-bullet in the structure. Yes (maybe) you can not be especially fluent in fit.

That's absolutely not true! Offers are extended based on a candidates spikes in certain dimensions of the interview (vs. other peers who are extended offers), assuming a hygiene level is reached on other dimensions. For example, if your structuring is "through the roof" and you made a small math mistake in one of your interviews, that is usually not a deal breaker, etc.

When there's been an obvious error during one of the final round interviews, there are often long discussions on whether interviewers see a systematic issue around the candidates performance or whether its a one-off. Needless to say, if you have made the same error more than once then thats an issue but at the same time, how you performed in first round and where you have shown improvement based on feedback are important considerations too.

Making the same mistake again will be game over. Otherwise, just do your best. Interviewers make mistakes too..nobody is perfect.

Actually, what they want to see from one round to the other is consistency of performance, but also the ability to work on the feedback provided in the first round.

They don't expect perfection.

I still made mistakes in my final round and still got the offer.

Here are a couple of other things that you can expect to be different in the final round:

1. Work on the feedback provided in the previous rounds. Most firms communicate the feedback from the previous rounds to the final interviewer. It's important then to show the final interviewer that you have a growth mindset and are reactive to feedback. This matters immensely. Make sure you are clear on your development areas and that you get the right support to polish them before the final interview.
2. Expect less structure. Senior interviewers already have the confidence that you are a decent candidate, your skills having been already vetted by their younger colleagues. They are rather more interested in your as a person and your way of thinking. So they might present you with an unusual case, or one that is created on the spot or no case altogether. Expect anything.
3. Focus on excellent communication. Senior interviewers care a lot about how clearly you communicate and how you manage to forge a connection with the interviewer. It's important to be top-down and concise as much as possible with your answers, while allowing the conversation to flow in a natural way.
4. Put yourself in their shoes. The one question senior interviewers are asking themselves throughout the interview is what will happen when they'll put you in front of a client they've groomed for years? Make sure that even based on this first impression you seem somebody who can be trusted and who can work with any client regardless of how difficult they might be.

Best,
Cristian

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Hi,

There is no one definite answer since its very subjective on both sides:

• You can make a mistake that seems small for you since you don't know all the case detailes but in reality, it's big
• You might have an interviewer who is very strict about such mistakes

Thus it's always better to demonstrate the best performance!

Best1

Cases are evaluated holistically, so you're right: Small errors won't move the needle if the rest of the interview was great. But they might be the straw that breaks the camel's back when the rest was just so-so. In this, second round interviews are the same as first round interviews.

Hello!

I also made some math mistakes in my 2nd round McK interview, so for sure it´s not the end of the world not doing a "flawless" interview.

However, it´s difficult to give you a judgement of yours... don´t think it too much, only fingers crossed now.

Best of luck!

Clara

Hi there,

You don’t have to be perfect in final rounds. However the bar will be higher.

When I coach candidates I give a score to each dimension of the case, so that they can get one number that shows how far they are from a first/final round pass and the reason why they are not reaching the bar. If you can, it would be great if you could get the same from your partners when you prepare.

Best,

Francesco

Hi,

It really depends on the interviewer, business demand, performance of other candidates and many other factors.

If you tried your best then nothing to regret.

(edited)

Hi there!

The interviewers won't pay attention to your errors when making a decision if you perform really well.

Nobody's perfect and you don't have to be either, but it's crucial that you do your best in order to achieve something and are able to correct your mistakes.

Do you need any further help?

GB