In the frequently referenced FAQ question, Must All Answers Be Referenced there is an exemption:

There are some types of questions that we can safely answer without needing references, however, such as claims that blatantly violate some laws of nature or known scientific facts (around high school level). For example, debunking a claim about a perpetuum mobile, linking to Wikipedia's article about the laws of thermodynamics might be advisable, but only for the reader's convenience.

This has been called into dispute in a recent answer to an old question: Do electronics have a startup cost?

(I am looking to solve the generic issue, not the specific one related to that question.)

In short, the question challenged a fairly basic concept that is at the high-school level. The first draft of the answer addressed the question by using the same high-school level concepts, with no references. It was challenged (by me) for having inadequate references, and the author defended themselves by saying the concepts were basic ones taught in many high schools, and therefore needed no reference..

Do you think this defence is fair, and that it was inappropriately tagged for having no references?

Do you think the initial complaint about the lack of references is reasonable, because the answer is just a repeat of the claim?

If you think the complaint is fair, do you think we should edit the FAQ to explicitly state that (for example) if the question itself challenges a concept taught in high school, it is necessary to provide references to support the high school level "facts", or is this rare enough to not need explicit calling out?

What is your view?

  • The policy explicitly states that 'high school level' knowledge does not require citations. If you want to change the policy, let's have that discussion, but that's what it says at present. No two ways about it, and no possible way such a defence is not presently 'fair'.
    – user207421
    Feb 17, 2016 at 8:02
  • 1
    @EJP: The option of changing the policy is what this question is about.
    – Oddthinking Mod
    Feb 19, 2016 at 1:13
  • Possible duplicate of High school science and referencing every claim
    – DavePhD
    Feb 19, 2016 at 21:31
  • @DavePhD that question has a great title, but the body is very specific. It is also downvoted. I'd rather close that as a dupe of this, than vice versa.
    – Sklivvz
    Feb 22, 2016 at 9:42
  • @Sklivvz yes, seems logical to close the other one at this point
    – DavePhD
    Feb 22, 2016 at 12:52

4 Answers 4



No doubts whatsoever here. At the very least, citing a high-school level textbook is an easy way of supporting the answer, and of proving that the answer is high-school level.

Supporting this kind of answers with references has a low cost to the answerer. On the other hand, answers that dismiss a claim because "it's obvious", are not beneficial to the OP or the site at all.

Let's invest 5 minutes and reference such answers!


Communication with others relies on sharing a certain level of a common understanding.

Even just looking at Stack Exchanges, different sites have a different base-level expectation of what a typical user will understand. For example, compare English Language & Usage versus English Language Learners, or Math Overflow versus Mathematics. They have similar subject areas, but quite different expectations about the level of knowledge of their users.

Our rule for providing references needs to have a lower limit - a level of understanding that we can assume with references - or else half the answers will need to start "Chemistry is the study of the properties and interactions of matter. Matter is made of atoms, which are the basic unit of a chemical element." and build their way up until they can talk about the meat of the science in the question.

For Skeptics.SE, I would characterise the level we mainly seem to target as "intelligent, high-school-educated adults". We might reasonable expect them to understand that Helium is an element, but not expect them to recognise the proper meaning of a p-value.

An answer that mentioned in passing that the Earth orbited the sun about once every 365 days would not require a reference. An answer that relied on the current length of a mean tropical year being 365.24219 days would require a reference.

This is the reason behind the quoted rule explaining that you don't need to provide references for subjects that would reasonably be covered in high-school classes.

However, sometimes this isn't sufficient.

Sometimes, a person asking the question clearly shows they do not have that requisite level of knowledge. It may be explicit; Reddit's ELI5 (Explain Like I'm Five) is a popular format for people declaring they don't have sufficient background knowledge to understand typical explanations. It may be implicit, when they don't understand something that is obvious for anyone with a background in the area.

In such a case, it is reasonable to lower the threshold of facts that require references - i.e. to provide references to facts that we would like to think are common knowledge, but the questioner demonstrates are not.

Alternatively, someone could know what the high school teachers told them, but not actually accept it.

So, for example, if the question was about whether the Earth was flat and/or whether the Sun orbited around the Earth, it would not be sufficient to merely reply "The Earth orbits the Sun. It is high school level astronomy." That is begging the question. You need to show how we know that the Earth orbits the Sun.

  • 2
    I think it would be good to point out that a reference is required if the point being sustained is "core" or whatever answers the question and not a side point. I think that's what you are getting at in the second part of your answer, but you are not calling it out explicitly.
    – Sklivvz
    Feb 22, 2016 at 9:45


It's important to reference key points, regardless of their assumed level as to do otherwise invites original research.

There's a big difference between something being 'high school level' and being correct, relevant and applied in an appropriate situation. By taking the extra few minutes to find appropriate the references, it makes it much easier for readers to ensure the information is accurate and useful.


I just happend upon this answer in the Electronics stackexchange: https://electronics.stackexchange.com/questions/217860/how-can-you-calculate-battery-run-time/217875#217875

The answers thus posted about using mAh = (hours of current draw) * (current draw) are for ideal batteries and will not be good for a calculation like this.

Like the answer in question this answer attempts to improve existing answers by providing a theoretical basis for a reported effect. If you further read the answer however, it clearly links to an article explaining that high school level electronics is WRONG and should not be used in practical application because it relies upon an ideal battery.


It's worth noting that there are more distinction's here than just 'high school knowledge' being referenced. For example the answer in question:

  • Applies a theoretical law to a question regarding a practical application.
  • Draws conclusions one two and three steps away from the theory
    1. Applies to real world electronics
    2. Lower resistance necessarily leads to higher power usage
    3. This leads to more failures on startup
  • Had several users ask for references
  • Relies upon knowledge that may be taught at highschool, but not generally known.

As such I wouldn't use this case to change the referencing rules, but as to reinforce the meaning behind those rules and prevent it being used as an excuse for Original Research for masquerading as presumed knowledge.

It's also worth noting that the content of the answer may in fact be 100% correct. This is not a comment of the validity of the answer, but the ability for others to quickly validate the answer.

  • Is there no knowledge of the world we can assume? If I say Paris is the capital of France, do I need to cite a reference to support that?
    – Oddthinking Mod
    Feb 18, 2016 at 23:33
  • @Oddthinking I see no reason not to if it's key to the answer - it takes two seconds to find an appropriate information and the research often uncovers new information. Since we're on the topic of Capitals, sit down and write out the capital city of Australia as well as Turkey, Switzerland, Morocco, New Zealand, Brazil, Tanzania, South Africa, Canada, Bolivia and Israel. This is clearly 'high school' level information, but I'd be interested in seeing what the publics accuracy: internationaltravellermag.com/…
    – NPSF3000
    Feb 18, 2016 at 23:44

None of the answers so far provide a reference that states references should or shouldn't be provided, and in that sense many that say references are always required are self-contradictory.

Better Living Through Judicial Notice Litigation, Volume 36, Number 1, Fall 2009 explains:

judicial notice makes life simpler: You don’t have to spend valuable time and money proving what everyone already knows. That’s better for the court, your clients, and you.
the Supreme Court also discussed when scientific “facts”—like the laws of thermodynamics—are properly subject to judicial notice, not proof. See Daubert v. Merrell Dow Pharm., Inc., 509 U.S. 579, 592 (U.S. 1993).

If it is good enough for the court of law, it seems good enough for stack exchange.

  • 1
    I don't see the contradiction. We are discussing opinions and philosophy on meta.stackexchange.com, not facts about the world on skeptics.stackexchange.com. We have different referencing requirements on the two sites.
    – Oddthinking Mod
    Feb 18, 2016 at 23:34
  • 3
    Also, I reject outright "good enough for the court of law => good enough for skeptics.SE". There are many methods for finding the truth (maths, courts, philosophy, prayer, trial by combat), Skeptics.SE focusses on one of these alone: scientific skepticism. It has different standards to a court of law.
    – Oddthinking Mod
    Feb 18, 2016 at 23:37
  • @Oddthinking SkepticsSE doesn't allow math to find truth; answers that use math are closed as theoretical. Answers that use science to find truth are closed too, for example if someone starts from quantum mechanics postulates and proves or disproves the OP, that answer would be closed as theoretical. If someone did an experiment to see if aluminum foil sharpens scissors: close as original research. It's more a watered down version of court, with some trial by combat. Here the person asking the question can answer it and accept his/her own answer, which is different than court.
    – DavePhD
    Feb 22, 2016 at 13:06
  • @DavePhD that's not entirely fair. We allow math. I'd love if we could allow science -- real science. What we actually disallow are "here's a toy model to sustain my wrong answer" or "here's some data with no error analysis to prove my point" answers. While these are not allowed, they aren't real science, either
    – Sklivvz
    Feb 22, 2016 at 23:57
  • @Sklivvz ok, maybe I misunderstood. Would an answer like mine here: chemistry.stackexchange.com/questions/41585/… be ok on SkepticsSE ?
    – DavePhD
    Feb 23, 2016 at 2:24
  • @DavePhD No, but such an experiment, while educational, is not good experimental science either. It would certainly not be acceptable in my high school science class, for example.
    – Sklivvz
    Feb 23, 2016 at 4:51
  • @Sklivvz true, it would be better to determine density of solid and liquid, over a range of temperatures, with multiple replicates at each temperature point, and calculate uncertainty in the density. And repeat for a variety of fats, not just 1.
    – DavePhD
    Feb 23, 2016 at 11:53

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