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What Thomas Edison expected job candidates to know (nytimes.com)
136 points by davidvaughan on Feb 15, 2013 | hide | past | favorite | 141 comments

http://www.pangeaprogress.com/1/post/2010/09/einstein-edison... 'While in Boston, Einstein was subjected to a pop quiz known as the Edison test. (...) A reporter asked him a question from the test. "What is the speed of sound?" If anyone understood the propogation of sound waves, it was Einstein. But he admitted that he did not "carry such information in my mind since it is readily available in books." Then he made a larger point designed to disparage Edison's view of education. "The value of a college education is not the learning of many facts but the training of the mind to think," he said.'

While context also has some part to play, in general I am with you in what you are trying to say.

BTW, are fictional characters counted as references? ;-)


From that article, In A Study in Scarlet, Holmes claims he does not know that the Earth revolves around the Sun, as such information is irrelevant to his work. Directly after having heard that fact from Watson, he says he will immediately try to forget it. He says he believes that the mind has a finite capacity for information storage, and so learning useless things would merely reduce his ability to learn useful things.

EDIT: Somewhat relevant (and OT) comic... http://theoatmeal.com/comics/tesla

If you're going to use Holmes as a reference, then you agree with Edison and disagree with Einstein.

Holmes was characterized as profoundly valuing facts (as well as methods of thinking), if and only if those facts were useful to crime-solving. He was noted, for example, for his monograph on tobacco-ash residues. That is, he knew so much about the details of tobacco ash that, upon sampling some ash found at a crime scene, he could infer many useful things from it. Another example is that he is so familiar with all the various mud around London that when he sees some dried, he can guess where it came from.

Holmes is, overall, preposterous. And his theories (the theories that Sir ACD put in his mouth) are almost entirely without evidence.

That said, theories without facts to work upon are like a level with no fulcrum.


I've said this before, and I'll say it again. Do not take advice from Sherlock Homes, because he is fictional and thus can be no smarter than his creator, a man who quite literally believed in fairies, and could not be persuaded that Houdini was not actually magic.

While I agree with your point here, I'd like to question the statement that a creation can be no smarter than its creator.

This may well be true if we're talking about real-time creation, but it's absolutely possible to put in more brain cycles into offline, pre-processed creation and get better results.

Right. There are at least two different types of 'smarter'. Thinking speed is one dimension on which a mind can scale, but not the only one. A moderately competent chess player may play at grand-master level if given centuries of dedicated time to think about each move, but no amount of time-per-move will make a chimp a good chess player.

I think there are two different kinds of facts:

1. Random facts that have no obvious connection to what you're working on. 2. Facts that come in use frequently, and form the basis of expertise.

I expect there were many facts that Einstein did have memorized, even though he could look them up.

Holmes is surely an exaggeration, but in many domains expertise is simply mastery of basic elements.

Understanding many little pieces lets you see the whole more clearly than someone who is missing parts. Experts have enhanced intuition.

This is a distinct type of knowledge from the depth of the pacific ocean. That kind of knowledge will not improve intuition if memorized.

Debunking of the sorry attempt at debunking.


I know this is offtopic, but it's a great point... There's a paragraph that says "This is a fair point." next to it. It basically says that we all stand on the shoulders of giants - and that other inventions allow new inventions to be discovered/developed. This is the EXACT reason I disagree with most patents.

Apologies for the off-topic rant, but it's one of my passions. I'm most probably preaching to the converted.

Thomas Edison invented the cylindrical Phonograph, and movies were beginning to just show up in 1921. I'd imagine knowing the speed of sound - especially how it relates to syncing with video - was of major importance to him, much more than it was to Einstein.

Context is everything.

I doubt Edison had a full understanding of the theory of operation for the phonograph he invented. I can't see how knowing the speed of sound in air could matter at all in relation to synchronizing audio with video, or Edison's motion picture camera. He could not broadcast sound from a speaker far enough for the sound to become unsynchronized with any video that was played.

It's somewhat of a trick question, as the speed of sound can vary greatly depending on the material it's propagated through. In air, it varies according to temperature and altitude.

Despite the space station being at an altitude of 370km, I'm sure sound travels through its air at about the same speed as it would in the open at sea level. So it's not altitude but density.

Is it important in this context to know exactly what the speed of sound is in feet per second without looking it up, or is it more important to be generally aware that sound travels through air via compressed air waves and that it is quite a bit slower than light, the details of which can be looked up when necessary? Are these executives going to be tasked with making lightning-quick product decisions involving physics calculations on a daily basis?

Regardless of the context, it's still a fact that that information is readily available in books.

Why is that so many people on this forum feel that the information pointed to by this link is of such great importance: https://gist.github.com/jboner/2841832

I don't know if that information is contained in a particular book, but it is certainly readily available all over the web.

Why do we care? Could Edison have had a similar interest, though focused more on his own business?

Separately, what good is knowledge of theory if you have no practical experience upon which to understand it? The candidates given this test were also supposed to be in line for the executive ranks. Having a general knowledge of geography, geopolitics and trade would seem to be fairly important.

It's also unclear from the article exactly how Mr. Edison interpreted or used the results. Frankly, it sounds like many of those quoted in the article were offended by being asked such "simple questions"... despite not being able to answer them. Perhaps Mr. Edison was interested in finding executives who didn't believe that common sense, mundane facts or important business details were beneath them and best left to others.

Those numbers are of practical importance to programmers in particular. They directly affect nearly everything we do to some degree. On the other hand, without knowing anything about you, I can pretty confidently guess that the identity of Leonidas and the process of tanning leather are not practical concerns for you at all.

Also, I would argue that memorizing those numbers themselves is unimportant and putting too much stock in them is a mistake (some are very likely a bit different on the computer you're working with than they were on the one used to compile the list — for example, hitting L2 cache is slightly faster than a branch misprediction on the i7 IIRC). The important takeaway IMO is the orders of magnitude at work.

If you were developing technical products in 1921, the process of tanning leather was probably very relevant, as were questions about the density of different kinds of wood, the sources and production of various metals, etc.

Just as a programmer should know the orders of magnitude of latencies, an industrial engineer in Edison's time should have a sense of the characteristics of materials he might be choosing between. For example, should the handle of a new tool you're inventing be made of leather-wrapped steel, or hickory (traditionally used for ax handles)?

The trick is not that the information is available but knowing where that information is, so that if needed, one could look it up.

I tend to want to remember the places (in this case, blogs, books, articles,etc.) where I could start looking to find a piece of information as more important.

A simple example of this is me wanting to learn Backbone.js. I have been following Addy Osmani's blog and know that he can be considered an authority on Javascript.

I am now following his Developing Backbone.js Applications book online - http://addyosmani.github.com/backbone-fundamentals/#mvc-appl...

I trust that I have picked one of the top people in this area to help me learn this. If I just Google, just the sheer amount of links to blogs, training sites, videos, etc. would be overwhelming. It would be likely that I would pick a resource that is not the best.

With the information overload that we have, you now stand out by being able to find (and apply) the information in a timely manner.

This is undeniably true, but I think misses an important correlation: in my experience, people who are best able to find and access "minor facts" like this when needed are precisely those who are commonly considered "walking encyclopedias". I strongly suspect this was true of Einstein too, even if he couldn't pull up that one figure.

I think penalizing someone for not knowing any fact in particular is silly. But throwing a ton of questions like this at a candidate just to see how many they hit has, IMHO, more value than is commonly admitted.

This view is even more correct now that "what is the speed of sound" is only a google search away.

Maybe Edison only asked these questions because of how long it can take to look something up in a book.

For example, would you hire a programmer who couldn't answer:

- name one or two html elements and what they are for

- what is a for loop, and when would you use one?

These can of course also be looked up in books, but already knowing the answer to those questions (and many more advanced questions) in a lot of what you're paying for when you hire a programmer.

Well, let's compare "what is the speed of sound" and "what is a for loop". Both are domain-specific questions, one for physics, the other for programming. For both I'd accept an answer that describes the notion or idea behind the concept and not a memorised instance of it.

So, for "what is the speed of sound", I would accept an answer such as "The speed of sound is the speed at which a wave propagates through a given medium"; though I expect an actual physicist to involve molecules, springs and so on in his answer. What I would not accept is a string of digits. A string of digits shows you know how to remember a string of digits.

Similarly, for "what is a for loop", an acceptable answer is one such as "A for loop is a construct for bounded (at least in principle, but you can have unbounded for loops in some languages) iteration over a series of elements, either generated on-the-fly or from a concrete container". The analogue to a string of digits for this question would be to give the BNF definition of a for loop in C. I think you'll agree that knowing C syntax doesn't show you know how to program.

Given two candidates (for a C programming position), I would of course prefer those who know the syntax. Both because that's one less thing they need to learn before they can become productive, and because knowing C's syntax is indicative of spending a lot of time programming in C.

So to return to your comparison, if I were hiring for a position that required working math where the speed of sound was required... I would treat knowing that constant by heart indicative of their knowing the rest of that subject matter by heart. I'd want to test a lot of that as well. "What is the speed of sound?" would be like a fizzbuzz.

But any reasonable person should be able to answer the speed of sound question. After all, the rule of thumb for estimating lightning distance is that every 5 seconds is 1 mile. Reciting a definition is no better than reciting a string of digits.

Are you saying that people who do not know that rule of thumb are not reasonable people?

I obviously am.

Chalk me up as unreasonable then, as I had never bothered to remember that rule.

That rule of thumb only works in a very small number of countries ;)

> The speed of sound is the speed at which a wave propagates through a given medium

That's really the only 100% correct answer as well, since the speed of sound varies by temperature, humidity and a lesser extent, atmospheric pressure. If Edison expected a discrete number, that would be kind of disappointing.

Sure I would. Some time back html did not exist, and knowing that someone decided <blink> was a good idea doesn't matter. And for loops only exist in some programming languages and are not that fundamental even if common.

I wouldn't even think to ask those questions in an interview.

Reminds me of a similar story with Henry Ford, where he said he doesn't need to know everything since with the press of a button on his desk he can summon someone who can relay the information to him.

Henry Ford was notoriously ill-informed. He sued a newspaper for libel after they said he was an idiot. In the trial they asked him in what year the revolution that founded the country took place. "1812?" facepalm

edit: unfortunate typo

And yet Ford was a fantastic innovator and worth $188 billion (adjusted for inflation) when he died! It really hammers in the point that general knowledge and intelligence are very different skillsets.

sued a newspaper for liberal? he really was an idiot.

The Ford story has a superficial similarity to the Einstein one, but in reality they're diametrically opposed. Einstein _understood_ how the physical world worked so he didn't need to carry around unnecessary "information". Ford, at least in the story, has neither "information" nor understanding.

The distinction is similar to the distinction made in philosophy between "knowledge" and mere "true belief".

> Ford, at least in the story, has neither "information" nor understanding.

He does have information, he has information that some people around him will respond to his requests for more information if it becomes necessary to have it. The power of delegation at work.

Of course Einstein is famous for not knowing his own phone number in Princeton. He didn't see the point in remembering things he could look up.

I have to nitpick there. I suspect Einstein is actually famous for his Special and General Theories of Relativity, and for his amazing hair.

I completely agree with this, especially for us living now, since we have access to virtually any information on the internet. However, I can see why Edison would ask seemingly pointless questions. First, while that information is readily available in books, going to a library to find the book with the information needed was much more time consuming than pulling up Google, so there is the convenience factor of memorizing random tidbits of information. Second, and perhaps more important, is the fact that Edison was an inventor, hiring people to help invent things. As an inventor, one needs to have a vast array of knowledge in many fields, and then to be able to make connections between seemingly unrelated items/topics. In our case (hacker news readers), we seek to combine separate entities in ways that no one has done before, creating a new product (read: app/website). Making connections no one else sees is at the heart of entrepreneurship, and invention as well, so having that wide array of knowledge could be see as invaluable.

When I was in the Army the officer in charge of my section commented that another PFC was better because he read the software manuals so he could answer questions that came over the phone.

I said I memorize things that I can't look up easily.

In the original link, I didn't see any claim that Edison was looking for correct answers, or that Edison knew the answers. Only that he looked at the paper for a bit and then dismissed the candidate.

For all we know, he was looking for people who deliberately ignored some subset of questions as irrelevant, or who demonstrated some quality of judgment such as questioning the appropriateness of the quiz verbally before starting, asking to take it in a quieter environment away from the arguing people, helping mediate the argument instead, stopping and asking for their first few answers to be checked to see if there was any point in them continuing, or ... anything at all, really.

How I read this: Einstein would have approved of candidates using Google.

Basically, it seems Edison wanted his executives to have his intense intellectual curiosity (he was a notable autodidact). If he knew the kind of people he felt he could lead effectively, and this was his perhaps-crazy way to identify them, this seems like a good test for those circumstances.

One of the most damaging things is when you have what Gabe Newell calls "rent-seeking inside the corporation," which is a neat economic way of describing bureaucratic political power struggles. And this is totally normal, expected behavior unless you find someone who is pre-aligned with the mission, goals and values of the organization. This becomes totally crucial at huge corporations like Edison's.

So this, in a sense, is a cultural test more than a knowledge quiz. Thomas Edison didn't want people who could win at 1920s Jeopardy!, he wanted people who were driven by the same non-monetary pursuits he had, possibly because it was his best chance to avoid BS artists, pleasant-but-ineffective workers and political strivers. I also have to think that it was because he was a pretty narcissistic dude, but that's another story.

To be sort of fair, Mr Edison was an engineer, and it was back in a time when there was more 'empirical' methods rather than predictive theories of why such and such happened. So, when there's an emphasis on building things, knowing all of this can be helpful. There's also a business type question in there, perhaps to keep an engineer's awareness of business needs in mind.

For example, as Engineering Guy Bill explains, http://www.youtube.com/watch?v=DIGqBb3iZPo, the method for discovering light bulb filaments was very much a search problem, so knowing as much seemingly distant facts about barrel wood, cork, optical facets might actually be important.

Questions about Cleopatra and so forth may have been to see how educated an applicant was. I wonder if those helped or hurt a candidate. I.e., did this person learn this on their own through curiosity or did they pick it up at school...

Disclaimer: I am not qualified to give opinions on any topic.

All of those are what I would call common knowledge that an average human being should know. Not that they are relevant in any way to the job Edison was offering - but they would serve as a GREAT way to indicate whatever a person answering these questions is well educated and well oriented in the world surrounding them.

There's an assumption there that there is some reason why some of these are relevant to "common knowledge". Perhaps they had recently been in the news or something...

For example, I guessed that Spitsbergen was in Austria/Germany. It's actually a town of <3000 in Norway. Not significant, until you realize that it was the subject of the 1920 Svalbard Treaty between 41 countries. The Edison list purports to be from 1921.

So yes, you are exactly right... the man wanted people that were actively self and location aware, nothing wrong with that.

Common knowledge as an indicator of business fit has been proven to be useless (and should be obvious on examination). Knowing which small town is in which country is simply irrelevant to whether a candidate apply for a management position can improve morale or productivity, or whether a candidate applying for a marketing position has any idea on how to convince customers to purchase a product.

Common knowledge simply has no relation to actual skill in a set field and neither does it have any relation to intelligence. This is doubly so true today with any of these questions being answerable within seconds on a smartphone, and the thoughts instead turned to actually using the information to accomplish something useful.

It's possibly a good indicator of how well they absorb information and/or how much they read or pay attention to the news, or wherever they are learning these random facts from. I'm not saying that means a lot though, and I definitely would have failed this test.

Not necessarily, there are too many variables. The person in question may not own a radio. He may have spent a number of months in hospital because his wife got sick. An older person may have learned one of the facts over twenty years ago, and has since forgotten it. By random chance, one of the facts may have been heard by the candidate 10 minutes beforehand.

In short: it's a good indicator of so many random variables as to be simply an indicator of chaos itself. Don't use anything like this in any kind of test in which the results count - you will invariably get the short end of the stick with one or more candidates. Stick to measures that directly affect the job at hand, and culture fit.

I'm sure the answers to the questions would correlate fairly well to that even if there is some noise. And since there are a lot of questions that would smooth out the ones people get right or wrong just by chance.

I'd add: Watching the reaction of a person when they don't have one or more factoids at their fingertips is also useful for measuring the temperament of people.

The fact that he torqued a candidate so badly that it resulted in a letter to the NYT tells you that Edison didn't miss too much by passing on that hire.

I don't see why a candidates willingness to stand up for themselves would be a negative trait, per se. If anything, it reflects poorly on the interviewer.

Because it is inevitable that an exec will be in a position where it is expected that (s)he knows something but does not.

There are many execs who will then react with a "willingness to stand up for themselves", and god knows that culture exists at some companies. Screening for people who have a different emotional response results in (imho) a higher-functioning team.

I think the mere fact that someone would feel the need to "stand up for themselves" in the face of a simple question says a lot about them.

The reactions seem to be to the entire interview process, and not a single question. Thus, we're talking about the "whole package", wherein the interviewer's attitude and demeanor are probably more important than any individual question.

All of those are what I would call common knowledge that an average human being should know.

I don't mean this in a rude way, but if you honestly believe an average human being will/should know all these, prepare yourself for a life of abject disappointment.

I am disappointed every single day. Forget asking people which countries border France, I know people who don't know which countries border their own country. Hell, I even know people who don't know the day the WW2 started/ended. Sure, you can get around it life without knowing these. It will cause you no harm, not knowing how the world works around you. Sure. But I would like to live in a world where people actually put some effort into their education,and not just openly boast around about not knowing stuff. Like it is a competition to be ignorant or something, I don't know.

I agree with the spirit and most of the letter of your comment. But....

Why is the day of the beginning and end of WW2 such a stand-out piece of trivia that you would expect every person who puts "some effort into their education" to know it? You say it as though you find it hard to believe that any responsible adult could lack this particular fact. For myself, I fancy that I know a lot of trivia, including a lot of war-history trivia, but I don't know the day of the year on which that war ended (in fact, the only war start/end date I can recall at the moment is the date of the WWI armistice, because my government reminds me every year).

More generally, I did not see a single question in the list in TFA that I would condemn a person for not knowing that particular question, although I definitely "would like to live in a world where people actually put some effort into their education", and in fact I see some practical value in knowing a lot of trivia.

EDIT: Wait, I just read your top-level comment. You believe that ALL of these questions are "common knowledge that an average human being should know"?? Did you read the list? The AVERAGE HUMAN BEING should know the third-smallest State in the United States of America?!? The average human being should know which country consumed the most tea before WWI? You think it's common knowledge (or was in 1921) who wrote "Home, Sweet Home", and the voltage of street cars, and Lincoln's birthplace, and the wood used in axe handles and kerosene barrels? Seriously? That is batshit insane.

Dude. Obviously you need to translate some of these question for modern times - it's hard to know who used most tea before WW2, but it's a fairly common statistic nowadays. Think about it for a second. At the time, when you actually had kerosene barrels laying around, you would know what there were made out of. There's nothing extraordinary to know where Lincoln was born. Home Sweet Home was only getting popular at the beginning of the 20th century, it's like asking somebody today whose slogan was "Change". Obviously everyone will answer Obama,but in a 100 years that will be of no meaning to anyone.

Sure, questions like the one about a lightest/heaviest wood is not so easy,but for a well educated person it should be of no issue. We have this issue nowadays where we don't remember anything - because our brains know that we don't need to. We are always a few clicks away from knowing anything we might need. We read an article and we don't actually remember any solid facts,because we know we can just come back and find them again. 100 years ago people were actually amazingly good with remembering shit, much much better than we are now. They would read something and that would stay in their brain.

WWI ended on the eleventh hour on the eleventh day of the eleventh month of 1918. The dickhead statesmen came up with this time to make it memorable. Do you know the hour that any other war ended? Unless it was tied to a mnemonic? If you do, shut down your computer and get some fresh air.

Sure, questions like the one about a lightest/heaviest wood is not so easy,but for a well educated person it should be of no issue

Are you trolling? I'd make an honest bet that less than 1 percent of people holding masters degrees could answer this. People would just guess (incorrectly) mahogany and get on with their non-trivial business. Hell, forget 1 percent. Less than .01 percent more likely. Harvard graduates can't even tell you why we have seasons.

I feel depressed that when I read his question, I guessed Mahogany.

> Obviously you need to translate some of these question for modern times - it's hard to know who used most tea before WW2, but it's a fairly common statistic nowadays.

I was not aware that Edison survived past WW2... Maybe you need to review the facts a little more. FYI, generally, in the time period that this article was written, the war referred to the great war, aka WW1

You've moved the goal posts from random Jeopardy-esque trivia to facts like what country borders your own, skipping the entire argument.

I am not completely sure what countries bound France nor the exact date of D-Day, because I don't value rote learning of insignificant stuff. Memorization of random facts is as useless as knowing nothing. I would appreciate much more if you can talk at length about one single topic and if you understand it pretty well.

I do agree that some people boast about their ignorance but that is another problem entirely.

Really? You think the voltage on a street car and the wood that kerosene barrels is made of is common knowledge? I would say that I knew maybe 1/3rd of the questions in that list.

Yes. Will I boast if I say that I honestly don't know just 3 things on this list?

Back when I was at school, we had all the subjects as mandatory, chemistry, physics, biology, history - there was no choice like you get today. So yes, I happen to know the weight of the air,or the lightest/heaviest types of wood. And if you like researching things(in my case - spending hours on wikipedia) questions like the one about optical lenses are easy.

And I am pretty sure that's what Edison was looking for - people who are curious about stuff and research it themselves. Common knowledge in my opinion,because in an ideal world I would like everyone to be that curious about the world that surrounds them.

I wouldn’t say you were boasting, I’d say you were lying. You happen to know off the top of your head that: African black wood is the heaviest lumber. That’s the first thing you thought of? Really? What wood kerosene barrel would have been made of in the 20’s. What the voltage of a street car was in the 20’s. Where Spitsbergen is (unless you have been there or in the area). What war material Chile exported to the USA in WW1. What the highest rise of tide is in North America . What state has the largest amethyst mine. Who invented the modern paper making machine (modern in the 20’s). What ingredients are in the best white paint. What the populations of Germany, Japan, England, Australia, and Russia are. What part of Germany you get toys from.

Uh-huh. You should go on Jeopardy, you would make Ken Jennings look like a clown.

First one,yes. Second one - I actually used to work in a wolframium mine in Panasqueira, Portugal,when I was 17 and learned A LOT about mines in general in my spare time. Kerosene has been used a lot in mining lamps,so yes, I did read about it. I did research about one of the first electric cars in the UK,that was used widely as a milk delivery truck - back from the same period, so I happen to know the voltage. Why did I need to be near Spitsbergen to know where it is? I used to know a guy who was a fisherman on the Barents Sea - he would tell stories of where they went, hence Spitsbergen. Also, I live in Europe, so I am fairly comfortable with pointing out where stuff it. I mentioned before, we had all the subjects at school, there was no choice like you get now. Write a couple of essays about WW1,you will come across random stuff like the war material exported from chile, guaranteed. Highest rise of tide I remember from looking up the tides when I was wondering as a kid how comes that Netherlands is not flooded by tides constantly, so I read a lot about it. No, I don't know which state has the largest amethyst mine, one of those 3 I didn't know from the top of my head. I know what is used in the white paint nowadays - I guess that counts,since I have no way of knowing what could be the best answer in the 1920. The same goes to population - but again, living in the middle of Europe helps with that. And toys are easy if you live in a country that imports loads of things from Germany,having a border with it.

And no, I am not interested in Jeopardy.

"All of those are what I would call common knowledge that an average human being should know."

"I actually used to work in a wolframium mine"

Credibility shot.

It wasn't about what you know it was about what he knows. The problem in judging people the way you do is that you assume that everybody else lives like you do and spends their time like you do. Some people digest facts for a living, some people digest facts for a hobby. Some consider learning a life long vocation, facts, skills the lot. So don't be surprised if someone has an encyclopaedic knowledge about seemingly (to you, at least) useless facts.

Apropos useless facts, did you know shellac was made from insects?

I love researching things. I spend way too much time on Wikipedia and watching documentaries. That doesn't mean I remember small details about everything.

For example: I remembered reading about the topics relating to some of the test questions, but was unable to answer most of them.

Remembering a bunch of relatively useless facts does not make you a capable professional.

Feel free to post the answers to the questions.

Given some of them are disputed (heaviest type of wood is one of about three depending on who you ask and when (some are nearly extinct and like all natural things, vary considerably)), some require knowing knowledge from Edison's timeframe (what planet was recently found to be enormous size - certainly wasn't Jupiter - possibly Neptune) and a couple are opinions (what country and city produce the finest china), I feel like there is a lot of leeway in the answers, but knowing all but three seems unlikely.

Considering in the 1920s the US was in the middle of converting horse drawn street cars into electric, and this is an application for EDISON, I certainly hope you would know that answer.

Kerosene was the most important fuel used up until the 1920s, so I'd imagine most people would have seen kerosene barrels personally. A few would have derived the type of wood via curiosity.

A street car? What's that? I've seen them in movies. I guess in the nineteen-twenties, knowledge about street cars might have been much more likely to have been in the minds of engineers that Edison would want to hire.

They still exist. In Toronto, streetcars are still one of the major forms of public transit in the downtown.


Yeah, I was exaggerating for effect. The point being that they are rare. They have double-decker ones in Hong Kong. http://www.youtube.com/watch?v=jHFizrDGlUo

How old are you, gambit?


Today is not 1921, mind you.

Common knowledge now with the Internet? Yes. At the time? No.

Those were difficult and discriminating questions at the time.

This is a time when poor girls who couldn't afford stockings wouldn't be allowed to go to school and the majority of people didn't have indoor plumbing let alone the luxury of books. Heck, 6% of possible candidates of the country were immediately eliminated because they would have not been able to read or write in any language, let alone know the arithmetic, physics, etc, required.

They're significantly less discriminatory than you would think.

Keep in mind that he's not interviewing every single person in the country, he's interviewing college graduates.

Not only was having a college education not as prevalent as it is now, the sole fact that the people who are taking this test have graduated from college eliminates every single one of the "discriminatory" accusations you are making. If anything, the college admissions process (an obvious prerequisite of the test) is discriminatory, not the test itself.

What is the point that you are trying to make? If somebody did not know how to read or write, they were not a suitable candidate anyway, and that's not discriminatory against illiterate people, like looking for someone with a maths degree is not discriminatory towards people without one.

I don't think you know what the word "discriminatory" means:

Adjective Making or showing an unfair or prejudicial distinction between different categories of people or things.

You may say that it is not practical to not be discriminatory. You can also say that it is not immoral to be discriminatory. Both of those may or may not be true.

However, it is certainly discriminatory to use a test that is biased towards educated white men with college degrees and access and time to read newspapers.

Yes it is, if you're hiring them for shoving shit around. If you hire for an engineering position (what was this Edison guy doing anyway?), then those fancy writing and math skills and whatnot might be quite necessary.

I don't see how being able to recall on demand who Leonidas was indicates education or being well oriented with the world. I know, but discovering that someone didn't know wouldn't change my evaluation of how educated they are unless they claimed to be a historian.

I read through half of them and completely disagree. Most of the ones I saw had to do with history and geography. Those are the two subjects you'd learn from a formal education that I care the least about. They have no bearing on your ability to manage a team or run a profitable business (unless the business has something to do with those topics).

Where is my time better spent? Reading the biography about an ancient historical figure or reading a programming book relevant to my profession (and passions)? I argue the latter, especially since I don't care about said historical figure.

"Should know", "well educated", "well oriented." All these qualifiers are subjective and are consequently meaningless. I could say the opposite of what you said and I'd be just as right (only taking into account what was written by us both).

You'll need to operationalize what you mean to make any sense, and then to be right you'll need to provide evidence.

"... but they would serve as a GREAT way to indicate whatever a person answering these questions is well educated and well oriented in the world surrounding them."

So then you have to decide, is having a person that is "well educated" and well oriented preferable to one that isn't?

An average American, at most, since about half of them are USA-centric.

I found the test very interesting. You have to keep in mind that Edison was a prolific inventor, who at the time was in the business of disrupting as many industries as he could. From that perspective, he was looking for people who knew a lot about the current state of technology and business, and also able to bring to bear knowledge from apparently unrelated areas.. Many of the questions are trivia related to the technology of the time ("who invented photography?", "where is platinum found", etc.). I think the expectation was that someone who was actively interested in technology would have picked up a lot of that sort of trivia along the way. Some of the less technological questions ("what's the capital of Alabama?") are probably just trying to evaluate how aware the candidate is of the world around them.

A similar list today, say for a candidate to help run a high-tech incubator, might consist of questions like "who founded Google? which is preferable to a seller, a 2nd price auction or a standard auction? where was the web invented? what's the geopolitical and technological significance of tantalum? are lithium batteries riskier than other battery technologies, why or why not? what's a typical price for web advertising (per click, or per impression)? what's a zero-sum game? what's a derivative?" (Those are just off the top of my head, I could probably come up with a better list if I thought about it for 15 minutes). In other words, not things that you must know in order to do the job, but things that anyone capable of doing the job would likely have picked up along the way.

I wonder if Edison viewed a lot of these bits of information as truly pertinent to his work (e.g., many of the questions seem to be about building materials and where to get them), and then just tossed in a few items of random trivia for good measure.

These... honestly aren't that bad. Not that I know all of them, but many of them, totally. And those that I don't are pretty context dependent, particularly those about sectors of the economy that have been de-emphasized or historical tidbits that have been de-emphasized.

Replace "what city produces the most laundry machines" with "which American city is known for producing cars" and "from where domestically do we get sardines" with "what part of the United States is known for producing wine"?

Note also that there are some ostensibly hard questions that seem blindingly obvious to people here now: "Where is Korea?"

Why are any of these good interview questions?

They aren't good questions for, say, a software engineer, but they might be useful for executives, which is how the Times article says they were used. If you're going to be analyzing potential business opportunities you probably should have a sense of different markets, their size, their relative strengths and weaknesses, etc. You should probably have a basic idea of where we get products and materials from and a basic sense of what different types of materials do. In our post-industrial society we don't care so much about sulphur and rubber and borax, but would you hire a tech executive who didn't know where electronics are manufactured? Would you hire someone who couldn't identify the regions of the US where the tech industry has a large presence? Would you hire someone who couldn't identify "six big businessmen in the United States"? If you can't answer these questions than you don't know anything about the industry and you probably aren't curious or engaged enough to keep yourself well informed.

If we updated this list to include things that are relevant to today's world, I would expect that a well-educated, well-informed person would be able to answer most of these questions.

I can see general knowledge type of questions useful for several reasons in the time Edison lived:

a) How good is the candidate at saying 'I don't know'?

b) Can the candidate handle repeated failures i.e., a string of "I don't know"?

c) Can they BS? Instead of leaving a blank, can they BS about something tangential?

d) Building hype around Edison. Imagine if the smartest person in your town failed to get hired. In the days of telegraph, the word of mouth would be 'only the best and brightest can become inspectors at Edison's factories.'

e) Head fake. Perhaps Edison really judged the candidates in some other way but made a big show of 'ignorant college grad' to prevent people from gaming the interview.

f) Make people that pass the test feel privileged. Its a common recruiting tool.

I think Edison was a good at spotting and using talent (yeah, using) for his own ends. I give him the benefit of the doubt on the interview process.

Perhaps if you are going to run an international business that may be interested in expanding to the Pacific countries, having employees that can physically locate Korea might be important. Apparently he couldn't "just assume" that every college graduate had ever spent time curiously inspecting a globe and developing a general knowledge of different parts of the world.

Never said they were good interview questions, but the implication elsewhere has been "these are impossible to know the answers to!"

because he knew the answers to them.

Just like a software interview - demonstrate that you know a bunch of stuff that we, in our company have & never will use. For many software jobs...its like hiring a mailing man based on his understanding of mail-delivery-cart mechanics.

Reminds me of Google's fabled interview process. And on that note, I find it very interesting that virtually all of these questions could be answered almost verbatim by Google or WolframAlpha.

I don't work for Google. However, I have never heard of their interview process involving trivia factoids. There are several other companies in the valley that are guilty of this crap but Google at least focuses on algorithm questions, scaling etc.

To give you an example of what I am talking about:

1. Figure out if a binary tree is a mirror image of another binary tree.


2. Describe X where X is a language specific feature. More amusingly, in machine learning interviews, pick one out of millions of algorithms that are out there that the interviewer knows very well, demand that the candidate answer and derive every single part of that algorithm.

There is a distinct difference between demanding that people rely on memory to solve a problem vs problem solving abilities to solve a problem. While both are certainly useful for a job, I am honestly not sure how exclusively devoting yourself to the former is better than the latter.

Google once required you to put together factual trivia with technical knowledge.

One question in an interview was something like: How many possible IP addresses are there per square meter of the Earth?

My first response was indignation. A lot of those questions are seemingly irrelevant. However, I think we need to put them in perspective of the business and time. Once you do that, A lot of them become something I would expect people to know.

Would he appreciate an intelligent guess?

If I didn't know how much a square foot of air weighed, could I represent it with x and then give a formula?

If he asked me who discovered the south pole and I asked him to clarify whether he meant who first reached the south pole, who first postulated that the earth, being spheroid, must have a southernmost extremity, or who first realized that the earth produces a magnetic field, would he be impressed or merely annoyed?

I'd be more interested to know how he reacted to the answers than the fact that he asked the questions.

From what I've inferred by reading about Edison, he probably would have feared you more intelligent than himself; and wouldn't have hired you on that basis, after taking the opportunity to chastise you for your lack of knowledge.

This reminds me so much of so many software engineering interviews.

I have mixed feelings over this.

On the one hand, knowledge is different than education. Knowledge is the possession of information. Whereas education is the ability to find information quickly and efficiently, and pass it through a filter of critical thinking. Questions like the ones on Edison's list measure knowledge, but not education.

On the other hand, in my personal experience people who possess seemingly "random" pieces of information such as the location of countries on a world map or the birthday of a jazz singer tend to be much more productive. Not because the random bits of knowledge they possess are related to the work they are doing, but because information like that gives them a wider perspective on everything and allows them to be better at "pattern-matching", i.e. drawing connections between seemingly unrelated fields and subjects. This is a very, very important skill for any knowledge worker.

There is a compound effect to knowledge though. The more of the bits you've got the more the bits you already had start to make sense. And at some point knowledge starts to beget new knowledge all by itself, ideas and hypothesis about how unknown stuff could work based on what you already know, and sometimes completely new stuff.

So even if knowledge does not automatically mean understanding or education it can be a precursor to it and it can make it easier to attain the latter.

Silly facts (baseball scores for instance) do not have that effect. So there is a definite division between the kinds of facts that you can digest and their future effects.

This reads like a "smart test" rather than anything written by an actual engineer. Of course, I've never seen any evidence that that Edison had any engineering ability other than the ability to demand engineers invent things, and then to engineer that he receive the credit for them.

Thanks for sharing the link to the interesting series of questions. As I read along, I tried to think about what the correct answer was--or how it would be defined--for the various questions. I imagine that today many of the questions about geography would be less asked, although knowing about other countries still matters for international business.

We often talk about company hiring procedures here on Hacker News. From participants in earlier discussions I have learned about many useful references on the subject, which I have gathered here in a FAQ file. The review article by Frank L. Schmidt and John E. Hunter, "The Validity and Utility of Selection Models in Personnel Psychology: Practical and Theoretical Implications of 85 Years of Research Findings," Psychological Bulletin, Vol. 124, No. 2, 262-274


sums up, current to 1998, a meta-analysis of much of the HUGE peer-reviewed professional literature on the industrial and organizational psychology devoted to business hiring procedures. There are many kinds of hiring criteria, such as in-person interviews, telephone interviews, resume reviews for job experience, checks for academic credentials, personality tests, and so on. There is much published study research on how job applicants perform after they are hired in a wide variety of occupations.


EXECUTIVE SUMMARY: If you are hiring for any kind of job in the United States, prefer a work-sample test as your hiring procedure. If you are hiring in most other parts of the world, use a work-sample test in combination with a general mental ability test.

The overall summary of the industrial psychology research in reliable secondary sources is that two kinds of job screening procedures work reasonably well. One is a general mental ability (GMA) test (an IQ-like test, such as the Wonderlic personnel screening test). Another is a work-sample test, where the applicant does an actual task or group of tasks like what the applicant will do on the job if hired. (But the calculated validity of each of the two best kinds of procedures, standing alone, is only 0.54 for work sample tests and 0.51 for general mental ability tests.) Each of these kinds of tests has about the same validity in screening applicants for jobs, with the general mental ability test better predicting success for applicants who will be trained into a new job. Neither is perfect (both miss some good performers on the job, and select some bad performers on the job), but both are better than any other single-factor hiring procedure that has been tested in rigorous research, across a wide variety of occupations. So if you are hiring for your company, it's a good idea to think about how to build a work-sample test into all of your hiring processes.

Because of a Supreme Court decision in the United States (the decision does not apply in other countries, which have different statutes about employment), it is legally risky to give job applicants general mental ability tests such as a straight-up IQ test (as was commonplace in my parents' generation) as a routine part of hiring procedures. The Griggs v. Duke Power, 401 U.S. 424 (1971) case


interpreted a federal statute about employment discrimination and held that a general intelligence test used in hiring that could have a "disparate impact" on applicants of some protected classes must "bear a demonstrable relationship to successful performance of the jobs for which it was used." In other words, a company that wants to use a test like the Wonderlic, or like the SAT, or like the current WAIS or Stanford-Binet IQ tests, in a hiring procedure had best conduct a specific validation study of the test related to performance on the job in question. Some companies do the validation study, and use IQ-like tests in hiring. Other companies use IQ-like tests in hiring and hope that no one sues (which is not what I would advise any company). Note that a brain-teaser-type test used in a hiring procedure could be challenged as illegal if it can be shown to have disparate impact on some job applicants. Thomas Edison's test might face the same challenge today. Thomas Edison or anyone else defending a brain-teaser test for hiring would have to defend it by showing it is supported by a validation study demonstrating that the test is related to successful performance on the job. Such validation studies can be quite expensive. (Companies outside the United States are regulated by different laws. One other big difference between the United States and other countries is the relative ease with which workers may be fired in the United States, allowing companies to correct hiring mistakes by terminating the employment of the workers they hired mistakenly. The more legal protections a worker has from being fired, the more reluctant companies will be about hiring in the first place.)

The social background to the legal environment in the United States is explained in many books about hiring procedures



Some of the social background appears to be changing in the most recent few decades, with the prospect for further changes.




Previous discussion on HN pointed out that the Schmidt & Hunter (1998) article showed that multi-factor procedures work better than single-factor procedures, a summary of that article we can find in the current professional literature, for example "Reasons for being selective when choosing personnel selection procedures" (2010) by Cornelius J. König, Ute-Christine Klehe, Matthias Berchtold, and Martin Kleinmann:

"Choosing personnel selection procedures could be so simple: Grab your copy of Schmidt and Hunter (1998) and read their Table 1 (again). This should remind you to use a general mental ability (GMA) test in combination with an integrity test, a structured interview, a work sample test, and/or a conscientiousness measure."


But the 2010 article notes, looking at actual practice of companies around the world, "However, this idea does not seem to capture what is actually happening in organizations, as practitioners worldwide often use procedures with low predictive validity and regularly ignore procedures that are more valid (e.g., Di Milia, 2004; Lievens & De Paepe, 2004; Ryan, McFarland, Baron, & Page, 1999; Scholarios & Lockyer, 1999; Schuler, Hell, Trapmann, Schaar, & Boramir, 2007; Taylor, Keelty, & McDonnell, 2002). For example, the highly valid work sample tests are hardly used in the US, and the potentially rather useless procedure of graphology (Dean, 1992; Neter & Ben-Shakhar, 1989) is applied somewhere between occasionally and often in France (Ryan et al., 1999). In Germany, the use of GMA tests is reported to be low and to be decreasing (i.e., only 30% of the companies surveyed by Schuler et al., 2007, now use them)."

One thing I have to say about this whole issue, after a thoughtful comment from another HN participant off-forum, is that hiring managers have to be prepared for the development of their workers. The programmer you hire today may be a manager three years from now. Being sensitive to how workers grow in the workplace is at least as important for managers as making a good hire at the beginning.

This is useful information, and a good, well-documented discussion.

However, I'm finding it kind of tiresome to see it at the top of every job discussion, particularly since it's so lengthy. I don't think this Edison post was meant as a serious suggestion for how hiring can be done.

Perhaps you could make a blog post or pdf that contains the copy-pasted text, and then produce a summarized comment that links out to this info for anyone interested?

I'm sensitive to the argument that hiring related submissions will give bad advice if this context isn't provided. But on the other hand the status quo is tiresome for those of us who have seen this comment over and over.

The FAQ included in my comment is slated to be a new page on my personal website. I certainly intentionally miss some opportunities to post the FAQ here on HN, as discussions of somebody's article or post about how to hire come up here more than once per week on average. Those threads often have very active discussion. Sometimes I post the FAQ, and other times I just lurk.

Agreed. I'm sorry, but it's getting annoying to see such a lengthy post on top of every job discussion.

This post is not in a FAQ (question-and-answer) format, which is unfortunate, because I think it would benefit from it.

Frequently asked questions might include:

1) What is a reasonable work-sample test for programmers? 2) Should programmer work-sample tests be assigned as homework, or should they be administered in person? 3) Will the very best programmers refuse to take work-sample tests?

Many of these have ambiguous answers, like the country that makes the best optical lenses, who invented photography, axe handle wood etc. There are different answers because they are either subjective (Leica, I presume he meant, but Zeiss would be a solid choice too), Photography was possible the french guy Niépce, or Fox Talbot in the UK and there were many US contenders for the title also. Axe handles are made out of many types of wood...

These questions seem rather pointless, it's a case of I know this, so you should too. If Edison had been born on the west coast he would have likely asked a different set of questions.

He probably relied on the popular options. If all your neighbours think of Leica as the best, there's no way you'd pick Zeiss in a pre-internet world without a Wikipedia that has a disambiguation page for every other term. Sure, people on the other coast might pick Zeiss, but how many people were willing to travel across a whole continent for a job interview in those days?

I'm speaking only from my own experience but as a software engineer observing other software engineers a surprisingly large percent of the the (imo) very best have striking degrees of general knowledge. That is, that could speak very well to many topics other than just software engineering and they have eclectic and deeply developed 'outside' interests.

I believe this runs counter to the current politically correct understanding of intelligence or if you prefer intelligence(s) - although I do believe in the latter.

Link is to a pdf... (Don't we normally indicate this in the title?)

So what? It's not like a research paper or anything, just an article that has been scanned.


yes - and we should we give a f.ck about Edison's views? The man was no better than a lowlife

And you're willing to admit that a webcomic convinced you of that?

That's just a neat visual summary that everyone can quickly scan. Kinda like that post about another thief of ideas - Zynga.

Heard of Ad Hominem? It seems to affect you. He might have been a thief, but he was a quite capable business man that many could learn from.

I think this list would certainly fail a lot of good, smart candidates, but it probably didn't pass many idiots. It's not likely that someone would know all of these facts and not be well-educated and intelligent. If he was truly getting hundreds of applicants and he didn't mind skipping some geniuses who didn't know facts, this seems like a good way to weed people out. Plus, it's pretty easy to grade.

More than anything, this makes it sound like Edison only knew how to get useful work out of somebody whose brain worked like his.

> "Only some thirty of the several hundred applicants have managed to pass the test, it is true, but those who did and thus became inspectors of the factory have made good in every case."

Of course, there's no control group... One might expect his half-baked trivia test to work a little bit (being a poor IQ test), but there's no way to know.

Part of me wonders if Edison wasn't concerned so much with the actual answers to the questions as how an applicant went about answering the questions, and how the applicant reacted in the face of the test. Or perhaps he cared about some questions, and threw in a bunch of random ones to see what the applicant would do.

Still, before there was no google/wikipedia so common knowledge and general interest was much more important.

Is there any reason to believe the connection between this list and the questions Edison actually asked is any better than, say, the connection between what a Google interview actually looks like and how the newspapers like to portray it?

Did Edison treat his engineers well? If not, should I care what trials he put potential candidates through? If he was the overly manipulative type, perhaps he was mostly interested in humbling the candidate...

+1 for use of ampersand ligature in "&c", i.e., "et cetera"

And the most important question of all, "Are you a big enough sucker to believe I will give you the $50,000 I promised for building the invention I asked for?"

I wonder what Nikola Tesla asked prospective assistants?

[T/F] Thomas Edison is a brilliant man of impeccable morals and character.

* And I bet if you circled "T", he'd zap you with a Tesla Coil and have you thrown out.

Some of these might have been more valuable in the days when you couldn't just Google anything in an instant to find the answer.

Was he serious with these questions, or were they sideways questions designed to suss out how the tested person thinks?

So what you're telling me is that people have always sucked at evaluating job candidates.

Useful if you want to hire someone you could steal ideas from... Someone like Tesla.

The prune question must be very important; it's on there twice.

You could say it came up regularly...

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