10 ms·

Whiteboards are not the problem- rather the questions that candidates are asked are bad. Asking someone to solve an obscure mathematical problem (the Two Egg p

by JTbane 8y ago

Whiteboards are not the problem- rather the questions that candidates are asked are bad. Asking someone to solve an obscure mathematical problem (the Two Egg problem seems to be in fashion) doesn't do much except test whether the candidate has memorized the answer.

ybrah 8y ago
Whiteboard problems are used to show that you can work through a problem, while communicating well about your thought process. They're also good general intelligence tests, if administered correctly.
- sidlls 8y ago
  That they're used for those things doesn't mean they work. They're especially not good general intelligence tests.
  - ybrah 8y ago
    I'd wager that the fact that many high power companies use whiteboards for interviews point to the fact that they're useful.
    - pjmlp 8y ago
      The fact that there are so many successful fast food chains points to the fact that the food is good and healthy.
    - sixstringtheory 8y ago
      This is appealing to authority/popularity. But since we’ve gone there, many high power companies also have a lot of chuckleheads running around.
    - aianus 8y ago
      Maybe they're only useful when you're a high power company with $200k+ total comp and more applicants than you know what to do with.
    - baal232 8y ago
      Divining rods are trusted by many, and have been in use for centuries. If they weren't a good way of locating water, why would so many people use them?
- ivanche 8y ago
  I think an obvious reason for this type of interview problems is because developers at work usually talk loudly while solving problems and write code without the help of any external resource while the clock is ticking in the background. Oh, wait...
  - lordCarbonFiber 8y ago
    What both you and the parent post you're deriding are missing is white-boarding (when done correctly) isn't about the problem at all. It's just an easy way to get a candidate in the room and construct a technical conversation. As an employer I don't care how great your skills are, if you can't walk me through your thought process for 45 minutes you're not going to be overly successful. If you can't incorporate feed back or engage when pressed to change your design you're probably not going to be successful. Do your recruiting right and you shouldn't need the white board to simulate whether the candidate can code at all (I think white-boarding with the intent of looking for named algorithms is a waste of everyone's time), instead you want to see if they can synthesize information, engage with other people, and otherwise display the soft skills that tend to be much more useful metrics for employee success than coding aptitude. Granted, my industry is known for not having deep coding problems to solve, this strategy might not be as useful in verticals that require more technology chops.
    - ivanche 8y ago
      "When done correctly" is the key here. Alas, in my experience I was usually heavily penalized if I kept my mouth shut for as little as 15-20 seconds because interviewer "couldn't see my thought process". At the same time expecting from me to write syntactically and semantically correct, industrial strength bug-free code with optimum space and time performance for a problem I never ever encountered with the interviewer "helpfully" distracting me 4-5 times a minute.
    - krisdol 8y ago
      >As an employer I don't care how great your skills are, if you can't walk me through your thought process for 45 minutes you're not going to be overly successful. If you can't incorporate feed back or engage when pressed to change your design you're probably not going to be successful. The post you're responding to makes a great point that this isn't the normal working environment for 99% of actually-writing-code developers. I discuss and iterate designs with my coworkers/leads/managers/architects just fine, but a surprise algorithmic problem you have to simultaneously solve, draw on a whiteboard, and constantly present to an audience while being timed isn't something I have been great at. I bet many others aren't either. I got good at it after a few interviews last time I was looking for a job; but if I hit the interview trail again today, I'm confident that I would flounder in that setting for a while. Imagine if, instead, the candidate worked out a project -- maybe at home, or maybe in an interview room for some time -- then you take time to review and understand their work and then go through this back-and-forth process of discussing their work. This would also benefit the candidate's understanding of how you collaborate to problem solve in your work environment. The problem with this approach is that it requires the interviewer to actually invest time to understand the candidate's work. Anyway, I hope you see why many see it as a problem that the process for a candidate to succeed at a job interview is to practice interviewing skills rather than demonstrating their engineer skills.
- spamizbad 8y ago
  > They're also good general intelligence tests, if administered correctly. Is there any scientific evidence to support that, or is that just industry hokum?
- jaredklewis 8y ago
  > They're also good general intelligence tests, if administered correctly. And communism probably redistributes wealth if it is administered correctly. If companies want to hire based on general intelligence (not personality, team work, communication and so on) then they should administer IQ tests, which are based on a century of rigorous research. That would at least give you a fighting chance of measuring G. Why do you think white boarding can measure general intelligence?
reificator 8y ago
> the Two Egg problem seems to be in fashion When not in an an interview I like playing with these kinds of problems, but if I look it up I'll probably find interview prep where it shows the answer as well. Could you summarize just the problem please?
- trevorcreech 8y ago
  "You are given two eggs, and access to a 100-storey building. Both eggs are identical. The aim is to find out the highest floor from which an egg will not break when dropped out of a window from that floor. If an egg is dropped and does not break, it is undamaged and can be dropped again. However, once an egg is broken, that’s it for that egg. If an egg breaks when dropped from floor n, then it would also have broken from any floor above that. If an egg survives a fall, then it will survive any fall shorter than that. The question is: What strategy should you adopt to minimize the number egg drops it takes to find the solution?. (And what is the worst case for the number of drops it will take?)" http://datagenetics.com/blog/july22012/index.html http://datagenetics.com/blog/july22012/index.html
  - reificator 8y ago
    Much appreciated. Hmmm, that's an interesting question. It's the Price is Right closest without going over solver... Practical answer, drop from the first floor and then the second. You're probably not going to make it to the third. I don't want to put my actual answer in case others want to solve it. But I will say there's an obvious solution, but if you apply one of the hard problems of computer science you might eke out a bit of an edge. EDIT: Actually I don't think that's right. I think the answer varies based on your expectations, and should be tuned after each run if you run the same test multiple times. I do have a good starting point in mind though.
    - robotmlg 8y ago
      > closest without going over That's The Price Is Right, not Wheel of Fortune ;-)
brokenwren 8y ago
Well said!

by JTbane 8y ago

ybrah 8y ago

Whiteboard problems are used to show that you can work through a problem, while communicating well about your thought process. They're also good general intelligence tests, if administered correctly.

sidlls 8y ago
That they're used for those things doesn't mean they work. They're especially not good general intelligence tests.
- ybrah 8y ago
  I'd wager that the fact that many high power companies use whiteboards for interviews point to the fact that they're useful.
  - pjmlp 8y ago
    The fact that there are so many successful fast food chains points to the fact that the food is good and healthy.
  - sixstringtheory 8y ago
    This is appealing to authority/popularity. But since we’ve gone there, many high power companies also have a lot of chuckleheads running around.
  - aianus 8y ago
    Maybe they're only useful when you're a high power company with $200k+ total comp and more applicants than you know what to do with.
  - baal232 8y ago
    Divining rods are trusted by many, and have been in use for centuries. If they weren't a good way of locating water, why would so many people use them?
ivanche 8y ago
I think an obvious reason for this type of interview problems is because developers at work usually talk loudly while solving problems and write code without the help of any external resource while the clock is ticking in the background. Oh, wait...
- lordCarbonFiber 8y ago
  What both you and the parent post you're deriding are missing is white-boarding (when done correctly) isn't about the problem at all. It's just an easy way to get a candidate in the room and construct a technical conversation. As an employer I don't care how great your skills are, if you can't walk me through your thought process for 45 minutes you're not going to be overly successful. If you can't incorporate feed back or engage when pressed to change your design you're probably not going to be successful. Do your recruiting right and you shouldn't need the white board to simulate whether the candidate can code at all (I think white-boarding with the intent of looking for named algorithms is a waste of everyone's time), instead you want to see if they can synthesize information, engage with other people, and otherwise display the soft skills that tend to be much more useful metrics for employee success than coding aptitude. Granted, my industry is known for not having deep coding problems to solve, this strategy might not be as useful in verticals that require more technology chops.
  - ivanche 8y ago
    "When done correctly" is the key here. Alas, in my experience I was usually heavily penalized if I kept my mouth shut for as little as 15-20 seconds because interviewer "couldn't see my thought process". At the same time expecting from me to write syntactically and semantically correct, industrial strength bug-free code with optimum space and time performance for a problem I never ever encountered with the interviewer "helpfully" distracting me 4-5 times a minute.
  - krisdol 8y ago
    >As an employer I don't care how great your skills are, if you can't walk me through your thought process for 45 minutes you're not going to be overly successful. If you can't incorporate feed back or engage when pressed to change your design you're probably not going to be successful. The post you're responding to makes a great point that this isn't the normal working environment for 99% of actually-writing-code developers. I discuss and iterate designs with my coworkers/leads/managers/architects just fine, but a surprise algorithmic problem you have to simultaneously solve, draw on a whiteboard, and constantly present to an audience while being timed isn't something I have been great at. I bet many others aren't either. I got good at it after a few interviews last time I was looking for a job; but if I hit the interview trail again today, I'm confident that I would flounder in that setting for a while. Imagine if, instead, the candidate worked out a project -- maybe at home, or maybe in an interview room for some time -- then you take time to review and understand their work and then go through this back-and-forth process of discussing their work. This would also benefit the candidate's understanding of how you collaborate to problem solve in your work environment. The problem with this approach is that it requires the interviewer to actually invest time to understand the candidate's work. Anyway, I hope you see why many see it as a problem that the process for a candidate to succeed at a job interview is to practice interviewing skills rather than demonstrating their engineer skills.
spamizbad 8y ago
> They're also good general intelligence tests, if administered correctly. Is there any scientific evidence to support that, or is that just industry hokum?
jaredklewis 8y ago
> They're also good general intelligence tests, if administered correctly. And communism probably redistributes wealth if it is administered correctly. If companies want to hire based on general intelligence (not personality, team work, communication and so on) then they should administer IQ tests, which are based on a century of rigorous research. That would at least give you a fighting chance of measuring G. Why do you think white boarding can measure general intelligence?

reificator 8y ago

> the Two Egg problem seems to be in fashion When not in an an interview I like playing with these kinds of problems, but if I look it up I'll probably find interview prep where it shows the answer as well. Could you summarize just the problem please?

trevorcreech 8y ago
"You are given two eggs, and access to a 100-storey building. Both eggs are identical. The aim is to find out the highest floor from which an egg will not break when dropped out of a window from that floor. If an egg is dropped and does not break, it is undamaged and can be dropped again. However, once an egg is broken, that’s it for that egg. If an egg breaks when dropped from floor n, then it would also have broken from any floor above that. If an egg survives a fall, then it will survive any fall shorter than that. The question is: What strategy should you adopt to minimize the number egg drops it takes to find the solution?. (And what is the worst case for the number of drops it will take?)" http://datagenetics.com/blog/july22012/index.html http://datagenetics.com/blog/july22012/index.html
- reificator 8y ago
  Much appreciated. Hmmm, that's an interesting question. It's the Price is Right closest without going over solver... Practical answer, drop from the first floor and then the second. You're probably not going to make it to the third. I don't want to put my actual answer in case others want to solve it. But I will say there's an obvious solution, but if you apply one of the hard problems of computer science you might eke out a bit of an edge. EDIT: Actually I don't think that's right. I think the answer varies based on your expectations, and should be tuned after each run if you run the same test multiple times. I do have a good starting point in mind though.
  - robotmlg 8y ago
    > closest without going over That's The Price Is Right, not Wheel of Fortune ;-)

brokenwren 8y ago

Well said!