Is it okay to ask for a minute during the middle of the interview when the interviewer asks a brainstorming question?

Absolutely. 

Always ask for time. 

The idea that you should always be answering on the spot was propagated by candidates through peer practice, not interviewers.

Interviewers don't expect you to answer on the spot. 

Here's also a resource you might find useful for brainstorming question focusing specifically on the different techniques you can use:

• Expert Guide: Mastering Structuring & Brainstorming

Best,
Cristian

Hi,

Always take:

• 1-2 min for initial structure. But the faster the better. 1.5 looks fine
• 30 sec to analyze the graph / table. Very often you can come up with more than one conclusion from the graph / table(e.g. main conclusion, outliers, correlations)
• 30 sec - 1 min for questions on creativity. It's really hard to be creative "On-the-go". Spend this time creating the buckets of ideas and then the ideas within the buckets.
• Up to 1 minute for the conclusion. Again, the faster the better. But always take the time! Your conclusion should be very well structured and your arguments should include supporting numbers and you need time to collect them. Spend 1 minute on collecting the numbers for the arguments. Remember that 70% of your arguments should have numbers

It's a bit more tricky with taking time during the case: 

• It's not OK to take 30 seconds and then come up with just 1 or 2 ideas. And then if the ideas are not correct to keep the science again. This is called "Guessing"
• It's OK to take 30 seconds, draw a new structure (or continuation of your previous structure) and come up with a structured way to approach the problem further.

Best,

Vlad

Hi A,

Yes, this is fine untill you get stuck and just try to win some time while guessing. To ask for half a minute up to 1.5 min for thinking according to the type of question is OK but, surely, the faster you get insights and give a structured answer the better it is.

Best