Hi there,

The short answer is that this isn't good, but it also by no means indicates you are out of the running (this comes down to so many factors).

(1) Is “giving the wrong conclusion” always a detrimental factor in case interview? Assuming that I did well in other parts, is there still a chance to pass this round?

Of course it's detrimental! You gave the wrong advice. You're really asking if this is an eliminatory factor, which it is not. If you did well in other parts then yes you can still pass.

(2) What is the best way to react if you've given a conclusion and the interviewer points out that the conclusion is wrong?

The best way to react in any unexpected interaction (i.e. they correct you, change the info, test your thinking, etc.) is the same. Stay poised, acknowledge their point, re-assess, and re-articulate based on the new information (thanking them for their input).

In your example, the problem is not that you had the wrong conclusion, but the wrong supporting facts.

The case is not about “getting” the right answer, but about being structured, logical and yes, avoiding analytical mistakes.

So if you did a math mistake, but your logic was correct AFTER that, then the conclusion is not the problem. The problem is the math mistake, and how serious it is.

Now if the interviewer points out the mistake, you just have to keep you poise, accept the new facts, and see how it changes your recommendation. If you do it well, you show that you can keep your face when dealing with a client, and that you are coachable. So in this situation, you have to reevaluate the conclusion and provide the updated recommendation.