Comments:

1. Desiato on April 7th, 2011 at 14:34:

   On the other hand, it *is* #1 in “Computers & Accessories” on Amazon.com ahead of the 13″ MacBook Pro. Not sure how much that says; Amazon isn’t exactly the premier channel for Mac sales.

Comments:

1. Desiato on April 7th, 2011 at 14:44:

   It’s not obvious to me that that’s a ridiculous question. Why do you think it is? Would you say that guesstimating is a useless skill?

2. Spaceman Spiff on April 7th, 2011 at 15:01:

   I would think that the answer could be one of two – either zero, or a googleplex…

3. John Sinteur on April 7th, 2011 at 15:20:

   I’m sorry, what does the question have to do with guesstimating?

   Here’s what I think is the first answer I would give:

   “What do you consider to be the boundaries of Shanghai for this question? Do you have statistical information on a) how many people live in residential buildings in this area, b) information on the kind of buildings used most often in this area c) the average size and occupancy of these buildings, d) building code information for the area? Do you need information on the rate of change in the answer over time? If you do not have answers to one or more of these questions, do you have time to wait and get an answer? If not, how large an inaccuracy are you willing to accept in the answer?”

   I fail to see any guesstimating happening in there.

4. Mudak on April 7th, 2011 at 15:50:

   The really scary question among the ones listed, though, is “Explain to me what has happened in this country during the last 10 years.” Is there really a way of answering this question without revealing some kind of personal or political leanings, even if you just give the facts? The events you include or omit are just as telling as anything else. Therefore, wouldn’t there be the potential for hiring discrimination on the basis of the answers you give?

5. Desiato on April 7th, 2011 at 16:28:

   @Mudak: Hmmm, interesting point. Maybe they’re filtering for people who can make dinner table conversation without falling into overt political opinionating?

   @John: So why is the question ridiculous?

6. John Sinteur on April 7th, 2011 at 16:50:

   There’s only a very small percentage of people for whom the number of bricks in shanghai is a relevant interview question – for example, you’re an investor and you need somebody to build a brick factory in the Shanghai area, and you need to make sure the factory isn’t going to be too big – in such a job interview, there’s a lot of questions I would ask about Shanghai and bricks, but the stated one isn’t one of them unless I want the candidate to walk out of the interview. But wait, you say, we’ve got a job where making good guesses is important – I’ve already shown that this isn’t a good question about guessing. So let me turn it around – give me an example where the question is not ridiculous.

7. dweasson on April 7th, 2011 at 17:39:

   John, the purpose of this question is not to GET an answer, it is to see how the potential employee HANDLES the answer. Does he panic? Does he BS? Does he say, “I don’t know, but I’d start trying to find out by seeing what they have in the way of census data….”?

8. John Sinteur on April 7th, 2011 at 17:42:

   If you would interview me for the job I described in question 6, and you asked me it like that, I would terminate the interview. If you need to figure out how I think on that level, for that kind of job, I shouldn’t be in your interview in the first place.

9. Desiato on April 7th, 2011 at 17:58:

   In many business situations, you need someone with analytical or predictive modeling skills. You’re trying to decide what business opportunities to take, and you need to sketch out some what-if scenarios with different growth curves, cost outcomes, etc to see how you might do. You need someone who will ask the right questions up front, know where to find supporting data, and know how to put that together into a reasonable model.

   A question like this, I think, tries to probe at roughly that kind of thing. You want to see what clarifying questions someone asks, what inputs they use for their “model”, how they plug in data, etc. It’s not about the specific numerical guesses they come up with, it’s about the “model”.

   Questions that have a simple, specific right answer aren’t useful. People either know the answer or they don’t. Who cares? You want to find out how people approach problems they don’t know the answer to yet. (Assuming that’s most of what they end up doing, which is common in many functions).

   I think of it as similar to being asked “should the NYT put up a paywall or not, and what should the pricing be?” You’re not going to give a specific answer to that in an interview–you’re going to describe how you would go about analyzing what you think the right business strategy is.

   The alternate approach is to ask “tell me about a business analysis you did and how you went about it”. There are two problems with this: the candidate gets to pick something they’re already familiar with (that’s not what happens on the actual job), and you get less ability to compare performance of different candidates on the same question. Asking the same question repeatedly of several candidates helps you calibrate both whether the question is reasonable and which candidates are better than others.

   It’s not like I think this is a great question. But it’s not clear that it’s a ridiculous question.

10. Desiato on April 7th, 2011 at 18:00:

    P.S. the best job I can think of to ask this question for are those B.S. analyst jobs where people try to guess how many Xooms have been sold by desperately looking for any correlated data they can get their hands on.

11. John Sinteur on April 7th, 2011 at 18:13:

    Okay, I stand corrected. You did indeed find a job description that works.

12. Desiato on April 7th, 2011 at 20:51:

    Heh. Which makes us wonder why you’re quoting the resulting estimates on the blog.

13. Joanna on April 7th, 2011 at 22:07:

    @Desiato – Your comments convos with John make this blog even more interesting. Applause.

14. Heisenberg76 on April 7th, 2011 at 22:10:

    Even if I find this particular example not particularly well chosen, a question of this kind tests the ability of the candidate to solve Fermi problems.
    ( http://en.wikipedia.org/wiki/Fermi_problem )
    The skills involved are part of science and engineering education.

15. Sue W on April 8th, 2011 at 0:58:

    All this seems to me to be a kind of torture. Unless as mentioned above you were interested in bricks (from my memory Shanghai was largely constructed of concrete, but I digress).
    Useful interview questions?

    One boss I had used to give every candidate a “coding test” which was a photocopy of the coding horror page of McConnell’s ‘Code Complete’ – the candidates were warned there would be a test. The task was to write down as many coding errors in that horrible procedure/function as they could in 20 minutes. Then we left the candidate alone for that time. A very good way to test fluency in writing. One or two candidates surprised us by interviewing well in a social sense, but being unable to write more than a few chicken scratchings.

    Everyone in the department had done the exercise. By the time we did this, Pascal was obsolete so most candidates were reviewing code in an unknown language – not a bad idea.

16. KC on April 8th, 2011 at 3:51:

    @John, they are not asking how to arrive at the answer, they are ask for your answer a specific question. The down and dirty answer is: number of residential buildings in Shanghai x average number of bricks in a residential building in Shanghai. Certainly the answer to this specific question is not ‘I need more information’.

17. John Sinteur on April 8th, 2011 at 8:01:

    Define residential. Define Shanghai. The answer may differ by 3 orders of magnitude depending on these two definitions alone. How large an inaccuracy are you willing to accept?

    @Joanna: I’ve known Desiato for close to 30 years now. I enjoy our disagreements quite a lot!

18. John Sinteur on April 8th, 2011 at 12:52:

    KC, let me try it your way. How’s this: 1 billion.

    I’m allowed to miss by 3 orders of magnitude. Depending on your definition of Shanghai, there’s between 5 and 20 million people in the area, which means that my answer is correct if an average house has more than 50 bricks per person and less than half a million bricks per person.

    In other words, it’s always correct, no matter what. Which means the question is meaningless.

    If I explain this you as the HR manager interviewing me, I’m putting you in an impossible position. Hire me, and realize you’re hiring somebody who’s seeing through your bullshit and didn’t actually answer your question, or not hiring me and hiring the next person who does answer the question by some guessing process, and realizing you’re hiring somebody who does not have the capability to see through bullshit.

19. Joanna on April 8th, 2011 at 19:24:

    @John – Oh good! I was hoping he wasn’t just a fleeting presence around here. I’ll stop interrupting now. Cheers.

20. Mike on April 9th, 2011 at 17:29:

    You should be able to answer a question like that is about 15 seconds. Stick to powers of 10. Look at a wall, about 100×100 bricks, so 10,000 bricks in a wall. Figure 100 walls in an average building (there’s more than 10, less than 100). So 1 million bricks per building. How many buildings in Shanghai? Gads, 1 million? probably more. I’d go with 10 million. So 10 million x 1 million = 10 trillion bricks. A reasonable ballpark answer in 15 seconds. You want better, yes we need better data. The interviewer is looking for your process.

Comments:

1. Sue W on April 8th, 2011 at 1:03:

   The farkwits are not buying enuff trash? What…? They have no money? Well let them use credit!