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Because they're not real logic questions and they don't predict anything. It's about the same as judging someone's programming/design/writing/etc. ability by ma

Because they're not real logic questions and they don't predict anything. It's about the same as judging someone's programming/design/writing/etc. ability by making them do crossword puzzles or Sudoku. The LSAT is filled with logic games, and they are nothing like a silly question like, "how many golf balls could you fit on a bus." They are actual logic questions that have a definitive answer that tests your reasoning abilities. Being good at brain teasers does not make you intelligent; it makes you good at brain teasers. And they don't help prevent Alzheimer's, so they're really just a way for board people to pass time.

DanBC 14y ago
> a silly question like, "how many golf balls could you fit on a bus." Why is it a silly question?
- rayiner 14y ago
  Because it makes all sorts of assumptions that are outside the scope of what you really want to test. First, it assumes familiarity with golf balls. I have friends who grew up in Manhattan who have never seen a golf ball. They may have seen one on TV, but that doesn't let you really gauge the size of something. Second, it assumes familiarity with buses, and assumes the interviewer and the interviewee are talking about the same kind of bus. Are we talking about a school bus or a big-city reticulated bus? Third, it tests skills you're not testing. I live in the city and take the bus all the time, and I don't know whether a bus is 20 feet long or 70 feet long. I'm not good at visually estimating measurements. That might be a skill relevant to a carpenter, but not so much to a programmer. Even if you assume you have the measurements, then you also have to visualize the packing structure of the golf balls. This also tests spatial skills, which are arguably not highly relevant to a programmer. Brain teasers are generally stupid because they are under formalized. I agree with the poster above. If you want to test logical skills, give someone a section of the logical reasoning section of the LSAT. Those questions were carefully designed to test logical reasoning and to avoid testing other things.
  - juiceandjuice 14y ago
    It's not a silly question at all. You can completely parameterize the answer in terms of bus volume and golf ball size, or define a "best guess" by explicitly defining your assumptions on the size of a golf ball or a bus in the question. Finally, you should at least be able to provide a magnitude. Or, you know, you could always just ask what size a golf ball, and bus is. It seems to me the only assumption the question makes is that a person could make some logical assumptions about the question, ask some logical questions, or ignore all assumptions and parameterize the answer.
  - DanBC 14y ago
    The desired result is not "X golf balls will fit in a bus" but the process of how the interviewee approaches the problem. Are they entirely baffled by the question? Are they stuck, with no idea about how to proceed? Or do they ask for more information from the interviewer? Interviews are not about quizzes; they're a discussion. This question is a great way to start a discussion with someone. "Well, I've never played golf, but I do play squash. So, I'll use a squash ball as a start." "I have no idea how big a bus is. Let's assume a cuboid of let's say 10 ft by 10 ft by 30 ft." "Really this question has some sphere packing stuff in there. Being honest, visualising that kind of thing is not my strong point. I'm much better at things like $TOP_THREE_HERE. So, I'll use a weak version first to get a ballpark figure. Let's just line the balls up in a grid (as if each ball is a cube), where each ball touches 6 other balls, or the some other balls and the floor, sides, or roof of the bus." If anyone is using the question as you've suggested then yes, it's a bad question and they've failed. But you've missed the point of the question.
  - bmelton 14y ago
    Generally speaking, when questions like these are asked (I used to work somewhere that did them, and was often responsible for evaluating the responses), nobody cares that you come up with the right answer. Rather, I should specify, the right answer looks like this: Let's say a golf ball is approximately 2 inches in diameter, and let's say that the bus is approximately 20 feet long on the interior, with seat backs that are approximately 6 inches thick, seats that are approximately 8 inches thick, sit 18 inches off the floor, and are supported with posts of approximately 1.5 inches diameter. The key is in being able to break down a problem, identify the challenges (seats are wonky shaped, for example), identify all the components of the problem (e.g., seats take up space, seat posts take up space, buses aren't perfect rectangles, etc.) and all that. For what it's worth, I've evaluated that question more than a few times during interviews, and I have absolutely zero idea how many golf balls you can fit into a bus. If you don't know what kind of bus, ask. If you don't know the dimensions, ask. If you're going to throw up your hands and claim that the problem is unsolvable (plenty of people do, some even got hired), then perhaps a job in solving problems with possibly unforeseeable parameters isn't the job you want. There are plenty of other problems with the question, sure, but the key is in being able to figure out what the parameters are, at least loosely define them, and come up with a strategy for working the problem out. In the best answer I ever got, the guy asked to borrow the whiteboard and started charting out equations to calculate it (with variables such that if he was off on the diameter of the golf ball, you could replace it with the correct value and re-run the calculation). I stopped him well before he got anywhere close to actually solving the problem and recommended he be hired. Of note, I do not now nor have I ever worked for Google, so I can't say how they perform those, if it is even true that they did, but that's how I've always approached them.
- VLM 14y ago
  Because it could lead to an algorithmic discussion of numerical integration by shells vs numerical integration by disks from integral calculus, a discussion about 1-3 sig fig engineering estimation and error estimation and error propagation, maybe a discussion about circle packing efficiency. It's an analysis of four things: How an applicant socially responds to ridiculous requests outside their previous experience, and how they handle initiating and architecting a "large" engineering project from a vague request, how mathematically well educated an applicant is, and how wide the knowledge level of the applicant extends (basically a psuedo IQ test, with all the legal risks that implies). This is vitally important for a handful of positions, but a complete waste of time for most positions, thus silly.
kalid 14y ago
I'd have to disagree with "they don't predict anything". Do you think P(intelligent|good at brainteasers) > P(not intelligent|good at brainsteasers)? I'm not saying it's the best test, most accurate, etc. but if someone is really good at brainteasers I'd post it's more likely than not that they're intelligent. There's probably false negatives with people who are intelligent but bad at brainteasers. But for a filtering test (when Google has too many applicants anyhow) I can see why they're used.

DanBC 14y ago

> a silly question like, "how many golf balls could you fit on a bus." Why is it a silly question?

rayiner 14y ago
Because it makes all sorts of assumptions that are outside the scope of what you really want to test. First, it assumes familiarity with golf balls. I have friends who grew up in Manhattan who have never seen a golf ball. They may have seen one on TV, but that doesn't let you really gauge the size of something. Second, it assumes familiarity with buses, and assumes the interviewer and the interviewee are talking about the same kind of bus. Are we talking about a school bus or a big-city reticulated bus? Third, it tests skills you're not testing. I live in the city and take the bus all the time, and I don't know whether a bus is 20 feet long or 70 feet long. I'm not good at visually estimating measurements. That might be a skill relevant to a carpenter, but not so much to a programmer. Even if you assume you have the measurements, then you also have to visualize the packing structure of the golf balls. This also tests spatial skills, which are arguably not highly relevant to a programmer. Brain teasers are generally stupid because they are under formalized. I agree with the poster above. If you want to test logical skills, give someone a section of the logical reasoning section of the LSAT. Those questions were carefully designed to test logical reasoning and to avoid testing other things.
- juiceandjuice 14y ago
  It's not a silly question at all. You can completely parameterize the answer in terms of bus volume and golf ball size, or define a "best guess" by explicitly defining your assumptions on the size of a golf ball or a bus in the question. Finally, you should at least be able to provide a magnitude. Or, you know, you could always just ask what size a golf ball, and bus is. It seems to me the only assumption the question makes is that a person could make some logical assumptions about the question, ask some logical questions, or ignore all assumptions and parameterize the answer.
- DanBC 14y ago
  The desired result is not "X golf balls will fit in a bus" but the process of how the interviewee approaches the problem. Are they entirely baffled by the question? Are they stuck, with no idea about how to proceed? Or do they ask for more information from the interviewer? Interviews are not about quizzes; they're a discussion. This question is a great way to start a discussion with someone. "Well, I've never played golf, but I do play squash. So, I'll use a squash ball as a start." "I have no idea how big a bus is. Let's assume a cuboid of let's say 10 ft by 10 ft by 30 ft." "Really this question has some sphere packing stuff in there. Being honest, visualising that kind of thing is not my strong point. I'm much better at things like $TOP_THREE_HERE. So, I'll use a weak version first to get a ballpark figure. Let's just line the balls up in a grid (as if each ball is a cube), where each ball touches 6 other balls, or the some other balls and the floor, sides, or roof of the bus." If anyone is using the question as you've suggested then yes, it's a bad question and they've failed. But you've missed the point of the question.
- bmelton 14y ago
  Generally speaking, when questions like these are asked (I used to work somewhere that did them, and was often responsible for evaluating the responses), nobody cares that you come up with the right answer. Rather, I should specify, the right answer looks like this: Let's say a golf ball is approximately 2 inches in diameter, and let's say that the bus is approximately 20 feet long on the interior, with seat backs that are approximately 6 inches thick, seats that are approximately 8 inches thick, sit 18 inches off the floor, and are supported with posts of approximately 1.5 inches diameter. The key is in being able to break down a problem, identify the challenges (seats are wonky shaped, for example), identify all the components of the problem (e.g., seats take up space, seat posts take up space, buses aren't perfect rectangles, etc.) and all that. For what it's worth, I've evaluated that question more than a few times during interviews, and I have absolutely zero idea how many golf balls you can fit into a bus. If you don't know what kind of bus, ask. If you don't know the dimensions, ask. If you're going to throw up your hands and claim that the problem is unsolvable (plenty of people do, some even got hired), then perhaps a job in solving problems with possibly unforeseeable parameters isn't the job you want. There are plenty of other problems with the question, sure, but the key is in being able to figure out what the parameters are, at least loosely define them, and come up with a strategy for working the problem out. In the best answer I ever got, the guy asked to borrow the whiteboard and started charting out equations to calculate it (with variables such that if he was off on the diameter of the golf ball, you could replace it with the correct value and re-run the calculation). I stopped him well before he got anywhere close to actually solving the problem and recommended he be hired. Of note, I do not now nor have I ever worked for Google, so I can't say how they perform those, if it is even true that they did, but that's how I've always approached them.
VLM 14y ago
Because it could lead to an algorithmic discussion of numerical integration by shells vs numerical integration by disks from integral calculus, a discussion about 1-3 sig fig engineering estimation and error estimation and error propagation, maybe a discussion about circle packing efficiency. It's an analysis of four things: How an applicant socially responds to ridiculous requests outside their previous experience, and how they handle initiating and architecting a "large" engineering project from a vague request, how mathematically well educated an applicant is, and how wide the knowledge level of the applicant extends (basically a psuedo IQ test, with all the legal risks that implies). This is vitally important for a handful of positions, but a complete waste of time for most positions, thus silly.

kalid 14y ago

I'd have to disagree with "they don't predict anything". Do you think P(intelligent|good at brainteasers) > P(not intelligent|good at brainsteasers)? I'm not saying it's the best test, most accurate, etc. but if someone is really good at brainteasers I'd post it's more likely than not that they're intelligent. There's probably false negatives with people who are intelligent but bad at brainteasers. But for a filtering test (when Google has too many applicants anyhow) I can see why they're used.