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Wacky interview questions

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Re: Wacky interview questions

#51
post #36

Earlier quoted context omitted.

"Candidate is contrarian for the sake of being contrarian, and avoided answering all questions." I know you're joking, and there is value to getting the interviewer to clarify the question and confirm assumptions. But some of your responses ("define be") are nitpicky to the point of "this guy wouldn't be any fun to work with".

"this guy wouldn't be any fun to work with". But I always show up for the weekly lets sing happy birthday to those who had their birthday this week . And sometimes I'm the one who brings the cake. That's the definition of fun[1]. [1] In corporate America.

Yeah, "fun to work with" probably needs to be careful defined, but the word "work" is the most important part.

It definitely doesn't mean "fun only during non-work bullshit".

Re: Wacky interview questions

#52
post #40

Earlier quoted context omitted.

Which would be more impressive: that I long ago memorized that the Earth's mass is about ~5.98E24 kg or that I could estimate it knowing Kepler's third law (T-squared = C * R-cubed) and orbital information about the Moon(28d@250,000miles), Earth (365d@1AU), and Mercury (88d@0.4AU), where 1AU=93million miles. Or that I could cross-check it by knowing the circumference of 25,000 miles to get the approximate volume, and…

Almost all of the interesting stuff comes after you've made your estimates (although the process of getting to the estimates is not completely uninformative). If the candidate performs well on this question, then they have shown: 1. They have the ability to reason about problems in a potentially new domain. 2. They have the ability to pare down a problem to what is important and what can be neglected. 3. They can mak…

I passed the first test on rote memorization. The second was nearly the same. Only the third would have given information about my ability to estimate, which isn't enough to give real information about those 7 bullet points. I remain doubtful about the utility of these tests.

There is nothing, for example, which probes my experience with statistics.

Here's a more in-depth test. We run an medical experiment on lab rats. The protocol says that we will experiment on 20 rats, and that a mortality rate above 30% is too high so we must stop the experiment. After 5 rats, 2 have died. Should we stop the experiment now? Why or why not?

One could look at that and say that a 2/5=40%>30% so of course it should be stopped - it's higher than the allowed rate.

A better response is to point out that if 10% is acceptable, then there's a 0.9^3 * 0.1^2 * C(5,3) = 7% chance that this is an expected statistical fluctuation, and that the experimental protocols should have given some guideline on how certain one needs to be in knowing if the mortality rate was too high.

An even better response would be to point out that this means the first three rats lived, and it was only rats 4 and 5 which died, as otherwise the experiment would have stopped earlier under this protocol. In that case the possible experimental states are: 1) first rat died, so the experiment stopped = p. 2) first lived, second died, stop = p. 3) first lived, second lived, third died, stop = p. 4) first, second, third lived, fourth died, fifth lived = (1-p). and 5) first, second, third lived, fourth and fifth died = p giving (assuming I recall how to do this correctly) p+p+p+(1-p)+p = 1.0 or an estimated mortality rate of p=0.3.

In other words, this experiment is allowed to keep on going under the given protocol.

But this sort of modeling awareness is not present in the three tests you mentioned, despite being directly relevant, I assume, to what a trader does.

Re: Wacky interview questions

#53

These aren't just wacky, they are stupid. "How many ping-pong balls can fit in a VW bus" is just about the worst question I've ever gotten. Little or no relation to software development. Here's what we do. Interested in feedback, please! Via the phone: * A few background questions (why are you looking for a job, what sounds interesting about what we are doing) (20-30 minutes) * A bunch of topgrading questions http://…

I see a little value in "Fermi problems" like ping pongs in a VW bus. I use one like it on a candidate's second call (first call with an engineer; takes place after our on-site recruiter has screened tehem). The point is to see how they handle a relatively intractable problem. The only real wrong answer is either a refusal to come up with an answer or an off-the-cuff guess with no explanation. If they at least try to…

Re: open book, what I meant was "not expected to know" means something that they can't do blindfolded. For a Rails person making a contrived app from scratch doesn't tell me anything other than they could type `rails foo` and run a few generators.

What I mean is that, I put together a few challenges with APIs we work with (or gems we've written, that sort of thing) and have them solve a problem that will require them to use their innate ability, drive, and Google/StackOverflow/etc. to solve the problem.

It's not something that they would be able to do without the internet. Does that make sense?

The contract thing is tough, although at least in NYC the market is so tight that there's really no risk of unemployment, but yeah, we wouldn't do relo + contract. We'd start them off as remote and see if that worked. If so, then relo; it's risky risky for both parties (especially in NYC) that it's kinda crazy to expect either party to agree to it.

The candidate has no idea what NYC is like, and the organization may be reluctant to fire a bad hire who just isn't fitting in because they feel bad. At least with a remote contract, no one has to move and we can see if we both like each other enough to get married. Then would come the offer + relo., or if it's not a good fit, end the contract (with 2 weeks notice at least).

Finally, I'd say the initial screen is a bit light. We used to have about a 1-2 hr. technical Q&A followed by Fizzbuzz-style questions, but that had a low false-positive rate so we got rid of it.

That is to say, the background work I did (googling them, stack overflow, github, twitter, their resume, etc.) was a pretty good filter at keeping out the obviously underqualified.

However, I'm considering putting it back as it helped give me a more nuanced picture of the candidates that I end up doing as part of the contract, and it might help to have some first-impressions ahead of time (but I am always worried about false first impressions clouding my judgement).

Re: Wacky interview questions

#54
post #39

These aren't just wacky, they are stupid. "How many ping-pong balls can fit in a VW bus" is just about the worst question I've ever gotten. Little or no relation to software development. Here's what we do. Interested in feedback, please! Via the phone: * A few background questions (why are you looking for a job, what sounds interesting about what we are doing) (20-30 minutes) * A bunch of topgrading questions http://…

> "How many ping-pong balls can fit in a VW bus" is just about the worst question I've ever gotten. The point of questions like this is "Does this guy have any common sense?" Some of my least favorite hires were people who were whip-sharp at the details of their chosen programming language, but then when hired, would go off and do crazy and impractical stuff with it. Whether or not the question accomplishes a good ev…

I think the "real world, open-book" problems have to be crafted well, but I think they give a good sense of "Common sense". They are set up that you can absolutely prematurely optimize or go down really crazy paths (and I've seen them happen).

You don't need another developer to pair program to get that - essentially you set up a clean computer with their editor on it and your testing/interview environment, and they can hack away while you watch.

But yes, if there's some way to get a candidate to pair program on actual, real code with real developers, it's invaluable. Just make sure they sign a contract stating they are giving you the rights to the code, and that they are adequately compensated for their time at some reasonable hourly rate.

Re: Wacky interview questions

#55
post #22

These aren't just wacky, they are stupid. "How many ping-pong balls can fit in a VW bus" is just about the worst question I've ever gotten. Little or no relation to software development. Here's what we do. Interested in feedback, please! Via the phone: * A few background questions (why are you looking for a job, what sounds interesting about what we are doing) (20-30 minutes) * A bunch of topgrading questions http://…

Are you hiring now? :-)

Sure: https://www.fundinggates.com/jobs/

:D

Re: Wacky interview questions

#56
post #47
post #45

Earlier quoted context omitted.

> The point of questions like this is "Does this guy have any common sense?" GROOOOOAAAAN Maybe twenty years ago, and maybe if you were the individual to think up the question. Honestly I'm so goddamned bored with these unoriginal blither-blather questions I consider them a strike against the interviewer and the company.

I actually have never asked an estimation question, but I understand the motivation for asking this kind of question. I'm curious--what do you ask in interviews to get at a candidate's common sense? It's not very easy to do. Or do you think you don't need to assess common sense at all? Maybe it's not, but like I said, a lot of the hires I later regretted came down to something like that.

> Or do you think you don't need to assess common sense at all?

shrug If we're talking developers... The ability to drive to the location on time, answer questions without going blank are good indicators of common sense for me. Extracurricular activities, anything from volunteering at an animal shelter, to making civil war models to home brewing beer, are huge in my book because they are a good indicator of a grounded individual. That mixed with some pair-programming should give more than enough information. YMMV.

Re: Wacky interview questions

#59
post #9

Earlier quoted context omitted.

I am pretty sure (and given this is HN I'm sure a googler will be along soon to confirm/deny this) that Google have a policy of no longer asking those kind of brain-teasers for their software engineering roles. They may still do so for PMs, etc. Certainly when I had my Google on-site for an engineering role I was spared the infamous questions that crop up in articles like this from time to time.

Boy, I hope so. I've got my on-site on Monday!

Hope it goes well for you! Even if, like me, you don't end up with an offer I think they're fantastic experience.

Re: Wacky interview questions

#60
post #52

Earlier quoted context omitted.

Almost all of the interesting stuff comes after you've made your estimates (although the process of getting to the estimates is not completely uninformative). If the candidate performs well on this question, then they have shown: 1. They have the ability to reason about problems in a potentially new domain. 2. They have the ability to pare down a problem to what is important and what can be neglected. 3. They can mak…

I passed the first test on rote memorization. The second was nearly the same. Only the third would have given information about my ability to estimate, which isn't enough to give real information about those 7 bullet points. I remain doubtful about the utility of these tests. There is nothing, for example, which probes my experience with statistics. Here's a more in-depth test. We run an medical experiment on lab rat…

Yes, this kind of statistical modelling is certainly very relevant. I don't want to give the impression that this was the only question I was asked, or that it covers everything you need to know about a candidate. The entire question and discussion took about 15 minutes. I was asked questions of a similar kind to the one you propose in the other 11.75 hours of interviews.
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