Tackling Guesstimates in Interviews

What to do when you only have 5 minutes

Recently, I’ve been getting a lot of questions on how to approach guesstimates in interviews. Though I’ve covered the basic approach to guesstimates here, there are a few additional points that one must take care of while answering questions during an interview as opposed to answering guesstimates in the comfort of a time-bound competition with other teams on paper.

1. Take a step back and think

So you’ve been asked a question which sounds like something the interviewer made up to on the fly, say, how many buttons do we have in this building? (Seriously)

Resist the urge to answer immediately, they’re looking for a Batman and not Flash. Request the interviewers to give you some time, perhaps 30 seconds, if you can’t think in 5. Pausing for 5 without such a request is also acceptable. Create a mind map of the exhaustive list of parameters you can consider. You may ask for a sheet of paper if you think it may be helpful and the request will be heeded. Let’s do that for this random question -

• Buttons : Colors, Sizes, Decorative, Elevator, Telephones, Computers, Emergency
• Building : Floors, People, Purpose of building

2. Clarify the Doubts

So you’ve thought of all the parameters that came to your mind. Now go on and clarify what has been asked. This helps the interviewer judge your ability to go beyond the obvious and look at the bigger picture.

• Did the interviewer only refer to buttons on clothes and not electronic buttons? Great, you don’t think have to estimate the elevator doors, computer and emergency buttons anymore. Less work!
• What time are we talking about? Is it a special day like a festival that invites people to that building? Are you in an office complex and it’s a weekend?

Not only do you showcase that you try to be exhaustive with your assumptions, you also limit the scope of your own solution. With the number of variables possible in a guesstimate, this improves your chances of giving a structured, unconvoluted approach which is easier to follow and critique.

3. Voice Your Thoughts

You’re considering the parameters in your head and are a complete pro at mental calculations but the interviewer can’t get into your head. The panel has to know how you think to give you the job. The numbers by themselves aren’t as important as the approach is. So speak it out loud, structured. You may even have more questions as you solve, and they’ll know what makes you ask the right questions. Some examples of things you should definitely mention:

• If you’re unsure about a figure and are taking fictitious numbers, you lack the knowledge to make an informed decision about Y and hence, you will assume they’re X on the basis of Z.
• The formula that you’re using. (Total popultion x Age group % x Income Group %)
• The reason for considering a parameter and how it is going to be used.

It can be a little intimidating to solve guesstimates in front of someone for the first time knowing you’re going to be judged, but at the end of the day, it’s like any other interview question, one designed to see what your mental capacity and approach is. Feel free to comment here or email me at [email protected] in case of any questions, would be happy to help!

Read more on guesstimates here.