What Is The Most Important Interview Question?

Magnet Technologies is in hiring mode ! I spend a substantial amount of time on interviews. Every interview is an investment as well as an important conversation. 

So how do we find the right person for the job? How do we find out the smart guy who is faking it? How do we find the right talent who is not good in English but is a Mozart in disguise?

Jessica Stillman of BNET Blog mentions that the most important interview question is :
What do you do in your spare time? 

The blog mentions the following:

“Understand a person’s obsessions and you will understand her natural motivation,” Bregman asserts. Of course what to look for when hiring a receptionist is no where near as clear cut as what to look for when hiring a pilot, but Bregman claims that the principle holds no matter what sort of job you are hiring for. Receptionists need to be outgoing, so passionate readers who spend hours upon hours alone will probably not excel in the position, though they won’t necessarily be terrible at it. But if a potential receptionist is a frequent hostess and loves to throw parties, you might just have found your star.

Good observation. It follows the often quoted idea – Do what you love to do, and you will never have to work again in life. From interviewer’s perspective, it gives an idea of person’s natural personality. 

Some believe the most important question is : Why should we hire you?

What do you think is the most important interview question?