In my answers, do I need to cite sources for my claims?

I'm accustomed to other sites, where references are a must-have and the rules are strict regarding them.

I've also read this blog which says that good answers to subjective questions should be based on experience or references (but this wasn't a subjective question).

Is the inclusion of references required, on this site? Is that (including references) merely an optional (not a mandatory) counsel of perfection?

If I can't be bothered to find a suitable reference, should I avoid posting an answer at all?

For example, this answer has no references at the moment. Is this okay? I don't doubt that it might be improved by adding references, but is it allowed at the moment?


1 Answer 1


Generally, citations are good to have. There are 3 different types of sources:

  • Reputable sources, such as major news agencies and scientific institutes (The Times, National Medical Institute, etc.)

  • Personal experience. This is information you have gained from your own studies. This is not info you have gained from reading other sources, this is info you discovered by yourself.

  • Secondhand personal experience, such as blogs.

Wikipedia is a bit of a special case here, see Wikipedia's own article for citing Wikipedia. (tl;dr: it's mostly good but double check everything)

Generally, the first type of source is always welcome. In particular, questions tagged require answers to be sourced as such.

The second type of source is also welcome. Generally, you should try to present your info in an unbiased and methodical way. Imagine you're writing a research paper using the info you found out (doesn't need to be anywhere near that fancy though, but it should be scientific in the same way).

The third type of source, honestly, isn't always a great source. Unless the article provides undisputable proof (i.e. multiple images showcasing what they mean), you can't really trust it. Anybody can set up a blog that says anything, and that doesn't make it true.

But back to your real question: How often do you need these sources?

Most questions don't need many sources, if any. Obviously, questions need the first type of source, but that's really the only question that requires it.

To quote Oxford Dictionary on citations:

There are only a few instances in which you probably do not need to cite your sources. You do not need to cite your sources if you are writing your own words, ideas, or original research. You also do not need to cite information that is considered common knowledge, such as:

  • facts that are found in many sources (example: Marie Antoinette was guillotined in 1793.)
  • things that are easily observed (example: Many people talk on cell phones while driving.)
  • common sayings (example: Every man has his price.)

So basically, if it's either obvious or so simple that it's common knowledge, you don't need to cite it.

In your example case, I agree that you don't need a citation. I'd suggest linking to the wikipedia article about the 70s/80s and protein combining, but that's it. I wasn't around for that era, so some more info would be nice. However, you don't really need a source, just a bit more info.

However, when in doubt: cite! You can't have too many citations. If it's easy to get a source for anything, go ahead and do it! Better to source it immediately than have to retroactively explain to people who are skeptical.

TL;DR: Use a source when it's not common knowledge. If it's obvious to those who know about it, you probably don't need to cite, just explain a bit more.

In your example case, it's okay as-is, though more info would be nice. (not necessarily a source)

  • Thank you. I think it's a good idea (a good compromise between "always" and "never"), to use a tag (scientific-studies) to identify which questions do, and don't, require a reference.
    – ChrisW
    Mar 25, 2017 at 19:25
  • Questions tagged statistics, too, presumably want a reference.
    – ChrisW
    Mar 26, 2017 at 12:41
  • @ChrisW hm, I didn't even realize we had a tag for that. But yeah.
    – Riker
    Mar 26, 2017 at 15:08
  • I don't think this definitely addresses when citations are required. Yes, it covers general academic conduct but not whether it applies on this site. I think this is a recurring issue and requires clear community guidelines: vegetarianism.meta.stackexchange.com/questions/200/…
    – Tom Kelly
    Apr 3, 2017 at 10:11
  • 2
    @TomKelly I think it does address that: it says that citations are required, if and only if the OP adds the scientific-studies tag to their question: which is the tag an OP can use to specify that they are looking for answers with citations to scientific studies. On topics without that tag, citations may (not must) be included in an answer.
    – ChrisW
    Apr 3, 2017 at 11:43

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