Why You Should Not Use Wikipedia As Your Primary Source

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It is no secret to anyone who has read my posts in this forum for a while that I do not like Wikipedia. I think that there’s a fundamental flaw with the whole concept and philosophy of it. While I think that it may be useful to many who need a quick lookup for something, it is unfortunate that even more are using it almost as their primary source of information. And this is scary considering that (i) the validity of the information being presented is never guaranteed and (ii) the pedagogical presentation of the material is often shoddy, making the subject even more confusing.

I often get asked to look at such-and-such Wikipedia entry, or someone is trying to convince me of something and using a Wikipedia entry as a “reference” to back up his/her argument. It is usually during such instances that I find inaccuracies, confusing statements, and something outright errors in such entries. I was doing my own search on something a few minutes ago, and I decided, out of curiosity, to see what Wikipedia has to say about “Work Function”. Now, keep in mind that this is a common terminology, especially for physics students, since the photoelectric effect is a “must-know” topic for these students. One would think that this should be a topic that a Wikipedia entry would get it right, considering how many people would look up such a thing, AND, the fact that errors and inaccuracy would, by now, be ironed out.


This is what I first saw on the Wikipedia page Oct. 8, and my last check today shows that it is still there.

work function wiki page

I posted the date in the screen capture as a date stamp on when this was first viewed.

The offending passage has been highlighted with a red box. Let’s look at it closely, shall we?

The description here is on what happened for an insulator (or a semiconductor, for that matter). The figure shown is the simplified band diagram for such a system (i.e. an intrinsic semiconductor, for example), and defines the various quantities such as the work function, band gap, electron affinity, etc. The problematic statement says this:

For an insulator, the Fermi level lies within the band gap, indicating an empty conduction band; in this case, the minimum energy to remove an electron is about the sum of half the band gap and the electron affinity.

The first part of that paragraph which says “…. For an insulator, the Fermi level lies within the band gap, indicating an empty conduction band …” is OK. However, the second part is very puzzling and an outright error : “… in this case, the minimum energy to remove an electron is about the sum of half the band gap and the electron affinity …”

Whoever wrote this is STILL thinking that the work function (Phi) is still the minimum energy needed to produce photoemission, as in the case of a metal. This is FALSE, and anyone who looks at the band diagram can tell. Half of the band gap plus the electron affinity is the work function Phi, but this is the energy between the vacuum level and the Fermi level. The Fermi level for insulator/semiconductor has NO STATES, and thus, no electrons to excite! After all, it resides in the band gap! So what is being excited here?

For an insulator/semiconductor, while the work function may still be defined as the energy between the Fermi level and the vacuum level, it no longer corresponds to the photoemission threshold! The photoemission threshold now is the full band gap energy PLUS the electron affinity. You need to excite, at the minimum, the electrons from the top of the valence band to the vacuum level. One can see this clearly by looking at the band diagram in the figure.

Now, you can tell me “But ZapperZ, why can’t you correct these errors, and provide a service to the community?” You will then have missed my point entirely. My problem isn’t with these errors. My problem is the WHOLE PHILOSOPHY of Wikipedia. I find that to be the fundamental flaw, that no one of any authority is being given the ability to write and edit stuff. The errors in the various entries are only the SYMPTOMS of the flawed philosophy. I could spend a lifetime correcting many of these errors (now why would I want to spend a lot of my own personal time to do that in the first place, no one has given me a good reason), and it would not change a thing about my perception of Wikipedia.

If you don’t know the topic you are looking up, and you are using Wikipedia as your PRIMARY SOURCE OF INFORMATION, I would be very scared if I were you.

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  1. hideelo
    hideelo says:

    I agree that it's imperfect, but to look up an equation, or something like that it's pretty good. The flip side is, don't take textbooks as gospel either almost all have some typos and unlike Wikipedia, it isn't constantly updated.

  2. filipv
    filipv says:

    IF "the errors in the various entries are only the SYMPTOMS of the flawed philosophy" THEN "Encyclopaedia Britannica" is also based on a "flawed philosophy" since there are as many errors there as in Wikipedia.

  3. filipv
    filipv says:

    “Please note that, as I stated, and has been pointed out by several members, I’m criticizing the use of Wikipedia as the PRIMARY source of information.”

    By its very definition, all encyclopaediae are a tertiary source of information. Therefore, you objection about using Wikipedia as a primary source may just as well be addressed to *any* encyclopaedia, not just Wikipedia.

    Basically, you’re presenting a (flawed) argument against all encyclopaediae in general. Your argument is not Wikipedia-specific in any way.

    Also, the title “Why You Should Not Use Wikipedia As Your Primary Source” is fallacious. It’s a loaded question.

    In similar manner, you could write an essay titled “Why you shouldn’t run over people with a BMW 320”. Not only you shouldn’t run over people with any car (not just BMW) but also you’re assuming that the reader does run over people.

    I suspect that the author simply haven’t grasped the Web 2.0 paradigm and this is yet another “wikipedia is wrong because anybody can write anything he wants in it” rant.

  4. filipv
    filipv says:

    What makes one textbook different, or better than the other? It is the way the material is presented!

    Encyclopaediae are not textbooks. Never have, never will be. Their purpose and concept is different.

    The idea that one can study a subject matter using Wikipedia is scary.

    Is studying a subject matter from any other encyclopaedia less scary? If “no”, then why point your rage at Wikipedia specifically? Why the title isn’t “Why you should not use an encyclopaedia as your primary source”?

  5. Semyuel
    Semyuel says:

    Guys, you are talking about entropy here. For example, when you go to restaurant to order some pizza, what you need to know about it? If it has cheese, tomatoes, mushrooms, onion and meal, thats all. What does cook knows about pizza? Much, much more, he knows everything that is needed to prepare this delicious dish from scratch the scope of information abut the same subject is very different, the entropy of pizza is different. Similar thing we face about Wikipedia. For a student or regular citizen – this is a great resource of easily accessible knowledge, but scientists SHOULD NOT base his or her conclusions and theories on Wikipedia articles. The source of study for PhD professor should be works of other scientists and real experiments. If you are studying something at PhD level, you have to work out at least several different sources, talk about it with other scientists, do experiments, otherwise, you are not a PhD but a cheater.

  6. thelema418
    thelema418 says:

    This post is contradictory because it says not to use Wikipedia as a primary source, yet it uses Wikipedia as a primary source for its argument.

    That said, mistakes occur in all types of literature. This week I read an Economist article on dewormers used in schools. The first release incorrectly explained the meaning of a p-value. The editors fixed this, but the new release is also oddly worded and confusing.

    It is important for readers to be critical of all material they read. Even peer reviewed literature.

  7. himagain
    himagain says:

    THE most valuable contribution of Wikipedia is that it allows ANY peasant access to put their own view.
    Imagine how much further Human Sciences could have been if Harvey ( on the circulation vs slosh around concept of blood) had access to an open forum!
    The key point of inestimable value here is that outsiders have access. Anyone can post or – importantly – read the discussions.
    Sure, it is flawed and there is reason to be highly suspicious of the people now controlling it, but without the Net which makes all things possible – it would be almost impossible still to access your own medical problems (much less your records!)
    Mass medication is a complex divisive subject and the principal weapon of those who rule us. Wikipedia is a first stop only and highly censored. THAT is a problem, but today even kids are smart enough to Google anything.
    I’m so old I remember when I was an Authority. I knew lotsa things most didn’t.
    Today, 10 y.o.’s correct me…..

  8. Jeff Rosenbury
    Jeff Rosenbury says:

    The search for truth is ongoing. Does Wikipedia add to that search, or subtract from it?

    Like any power tool, it can be used incorrectly and even dangerously. But it is a great tool for what it does.

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