Well it certainly looks and feels like after the recent subprime circus the whole industry is actively downsizing. The supply of junior (and not so junior) quantitative analysts is more plentiful than ever before. That brings memories of infinite amount of available java “developers” after the IT bubble of Y2K finally bursted. Consequently, it has become even harder to select a person with ample knowledge and skills which brings us to the second part of the series -
Brainteasers
One piece of advice – don’t! The brainteasers are said to assess “how a person thinks under stress”. Well, actually they turn out to be assessing completely different things of which the interviewers usually are/(choose to be) unaware. Admit to yourself that none of the brainteasers you are going to ask have been invented by you personally. You know that almost all of them come from folklore. Have you ever wondered how old they actually are? I am going to reveal this secret right now: the majority of the brainteasers I have encountered (in real life, in quant web forums, interveiw preparation guides etc) can be found in one ultimate source …drumroll… – the wonderful Martin Gardner’s books on recreational mathematics! You can find all the usual suspects there, the simplest ones being St.Petersburg paradox, “probabilty of second child being a girl”, the Birthday paradox and many more. Given the fact that lots of puzzles in those books are actually reprinted from his old column in Scientific American, it is a safe bet that a particuarly nasty brainteaser you are going to give to a shivering candidate is actually no less than fifty years old.
The point I am trying to make is that the chances that the interviewee has merely memorized all your clever brainteasers are very high. So by observing the correct answer you actually achieved nothing – and you have no reasonable way to figure that out. On the other hand this whole “thinking under pressure” concept has nothing in common with real life stressful “thinking” sutuatiations where one has a plethora of external resources to his/her disposal. Once again I reiterate the value of a skill of being able to locate an answer quickly by any means possible which includes finding it in books, research papers, web-published lecture notes, forums etc. Brainteasers provide no help here.
Finally here is one more thing that I have come to believe. By giving a brainteaser the interviewer acts exactly as a child giving a riddle to another child – deep down there always is unconscious hope to get a feeling of satisfaction from witnessing the counterparty’s failure. The reason why I consider that to be true is that often solving the brainteaser brings the candidate much fewer positive “points” than it brings negative ones when the question is not answered correctly.
The next installment will be devoted to the remaing part of a typical interview – technical questions.
