user115: I have possibly spent too much time on Skeptics.SE... but I think we should be a bit more strict in requiring good references for answers.
Take for instance these questions (I hope the answerers do not take this personally, I just took some random ones):
Why insects are so energy-efficient while flying?
The highest voted answer (at the moment, at least), does not cite any peer reviewed work, but makes some quite strong claims on aerodinamics of insects, which I think should be backed up by strong references.
The other answer, does indeed, cite some good references and is a much higher quality answer.
Still, the incomplete one got 7 upvotes, making me think that users of the site are OK with this kind of partial information... which is a pity.
(on a separate note, the question is quite vague, it is not really clear what the OP is comparing insects to... birds? planes? gliders? stones?)
Does artificial high intensity light damage permanently dark ecosystems?
Again, the only answer is of very poor quality, it makes big claims showing no proof whatsoever.
If body temperature is 37°C (98.6°F), why are most people more comfortable at around 21°C (70°F)?
Two answers here, with possibly reasonable explanations... but only vague references that give actual measured values. I am no expert in the field, so I find it hard to judge whether they are realistic physiologically.
So, my question is: should we have a banner for "lack of references" like they have on Skeptics.SE?

user389: Doesn't forcing the need for references defeat the purpose of asking an expert to answer the question? This sounds like a common problem in wikipedia which asks for references for things that may seem to be obvious to someone who is established in their field. Of course the opposite happens on Quora.
This is reasonable for questions that involve an explanation but where the assumptions don't need to be heavily backed by facts and it is the thought process and the postulates that are important
However, I agree with Rory, if an answer makes significant claims that should be but aren't backed, then the reference is likely key to that answer.

user1231: I'm slightly split, but favor citation use.
Many of the questions on here are so basic that anyone with a high school diploma should have a reasonable comprehension of the subject, or at least know how to Google "Why does evolution do X". Admittedly, I'm personally fine providing articles and studies for most of the basic questions - the information isn't difficult to find and copious.
Then, on the flip side, there are also a fair bit of "so specific only one guy who frequents the site might know it" questions, and those ones don't get touched for days or weeks (if ever). Those questions don't seem to require references because the knowledge is either gained through practical experience (how to perform some bench work, or how to get an enzyme to operate at peak efficiency) or there aren't references to be easily found (what does DNA sequence XYZ on the banana plant's genome code for?).
Maybe there could be a checkbox while the asker is writing the question? At the end have a little:
[X] Would you prefer references from academic or scientific knowledge-bases in potential answers?
Then just add a bolded section in the reply form or in the answer itself to encourage citations for the people that want them.

user540: When dealing with specific questions relating to areas of currently active research, questions regarding concepts which are easy to assign to a research area with frequent publications, it is of course very difficult to defend refusing to provide references. When someone asks, "do mutations of the gene ABC1 lead to cancer?", the answer is, in the procedural sense, trivial: You look for research examining ABC1 vs. cancer, either the research says yes, no, or maybe, or there is no research on ABC1 and the answer is we don't know.
However that still leaves classes of questions pertaining to biology, which are interesting and not common knowledge, but would not be answered directly by literature:

Answering a question may require taking several different given research findings, putting them together and making deductions from there. In this case you will have references for the premises, but your conclusion (and the correctness of your reasoning), which is the answer to your question, will not necessarily be confirmed by any publication (it may be that the question happens to be something few scientists would bother to publish on, because answering it takes so much effort compared to the career benefits).
The question may be too broadly scoped and interdisciplinary for a publication to deal with it. It may ask for synthesis of disciplines or fields which are just not combined very often by actual scientists.

While it is nice to have sources and it is a bad habit not to give sources for your claims, I think it wouldn't be too shocking to ask you to accept that the scientific community is not exactly objective, fair and impartial with regard to what science it prefers to do. I mean this in the sense that, out of all the questions and unexplained phenomena to which the scientific method is applicable (and for studying which experimental methods exist or can be feasibly devised), individual scientists as well as the community as a whole, will be more likely to research some and not others. One reason is that any scientific research project is done by human beings with careers to worry about (and it seems increasingly so as time passes and costs of research as well as the dependence on cooperation from the rest of the community and governments/funding agencies are growing), and they will at some point ask the question, "is doing this research worth the effort, time and money? Is that expenditure of effort, time and money something that I can afford, considering how many papers and cites I'll get out of it?"
Human curiosity, on the other hand, is at least relatively neutral - it doesn't really matter how complicated, useful, or career-friendly a question is for us to become curious about its answer.
This site (I assume) is meant to address the latter, rather than the former, and as such there will be times when a question is asked and finding sources is challenging. Therefore, naively expecting every answer to have sources would be quixotic. I think it would be more realistic to treat it as a guideline rather than a rule, with the caveat that "answers without sources are allowed, but you better have good reasons for not giving sources (and explaining those reason in the answer doesn't hurt)". The latter part, requiring an explanation for why sources are eschewed when they are, might resolve the whole problem entirely, in fact.

user67: To be frank, no. While I think citations make some answers better, and requests for citations are always welcome, I essentially don't participate in Skeptics because I find it's approach to things extremely tiresome. If Biology followed suit, I'd cease to participate here as well.
One can, of course, disagree with that. But I spend far too much time working on how findings are published and cited to have much faith that a single link to an arbitrary paper renders an assertion nearly as solid as Skeptics seems to believe it does.

user69: I personally like to see claims referenced thoroughly; I do tend to downvote answers that make abstract claims without reference and have applied the Citation Needed banner on a few previous occasions.
Having confidently said that, I had a quick look through my own answers and found this, which probably neatly falls into the categories that you describe above.  I think we should be careful, therefore, to limit our discussion to the problem rather than any user in particular.
Overall, I think I agree with Nico and LanceLafontaine that this is becoming a problem and we should set standards early on.
At present, until the community verifies that this isn't best practice and we get a full strategy in place, I'd reccomend that unreferenced material be:

Downvoted
Left a comment asking to add references
If particularly bad, flagged for moderator attention to get the notice added.

This does lead to the next question, what to do with answers that have been given notice but not improved over weeks.  For example all of these noticed posts.  I'm rather hoping that other posts have taken the feedback on board, added references and had the banner removed, not entirely sure though.  I'm not sure whether they should be deleted as I feel downvotes would be more appropriate however some extremely tenuous claims have got fair scores.
Suggestions for all would be really well received!

115: <p>I have possibly spent too much time on Skeptics.SE... but I think we should be a bit more strict in requiring good references for answers.</p>

<p>Take for instance these questions (I hope the answerers do not take this personally, I just took some random ones):</p>

<p><a href="https://biology.stackexchange.com/questions/2937/why-insects-are-so-energy-efficient-while-flying">Why insects are so energy-efficient while flying?</a></p>

<p>The highest voted answer (at the moment, at least), does not cite any peer reviewed work, but makes some quite strong claims on aerodinamics of insects, which I think should be backed up by strong references.
The other answer, does indeed, cite some good references and is a much higher quality answer.<br>
Still, the incomplete one got 7 upvotes, making me think that users of the site are OK with this kind of partial information... which is a pity.
(on a separate note, the question is quite vague, it is not really clear what the OP is comparing insects to... birds? planes? gliders? stones?)</p>

<p><a href="https://biology.stackexchange.com/questions/2891/does-artificial-high-intensity-light-damage-permanently-dark-ecosystems">Does artificial high intensity light damage permanently dark ecosystems?</a></p>

<p>Again, the only answer is of very poor quality, it makes big claims showing no proof whatsoever.</p>

<p><a href="https://biology.stackexchange.com/questions/2955/if-body-temperature-is-37c-98-6f-why-are-most-people-more-comfortable-at-ar">If body temperature is 37&#176;C (98.6&#176;F), why are most people more comfortable at around 21&#176;C (70&#176;F)?</a></p>

<p>Two answers here, with possibly reasonable explanations... but only vague references that give actual measured values. I am no expert in the field, so I find it hard to judge whether they are realistic physiologically.</p>

<p>So, my question is: <strong>should we have a banner for "lack of references" like they have on Skeptics.SE?</strong></p>
 389: <p>Doesn't forcing the need for references defeat the purpose of asking an expert to answer the question? This sounds like a common problem in wikipedia which asks for references for things that may seem to be obvious to someone who is established in their field. Of course the opposite happens on Quora.</p>

<p>This is reasonable for questions that involve an explanation but where the assumptions don't need to be heavily backed by facts and it is the thought process and the postulates that are important</p>

<p>However, I agree with Rory, if an answer makes significant claims that should be but aren't backed, then the reference is likely key to that answer.</p>
 1231: <p>I'm slightly split, but favor citation use.</p>

<p>Many of the questions on here are so basic that anyone with a high school diploma should have a reasonable comprehension of the subject, or at least know how to Google "Why does evolution do X". Admittedly, I'm personally fine providing articles and studies for most of the basic questions - the information isn't difficult to find and copious.</p>

<p>Then, on the flip side, there are also a fair bit of "so specific only one guy who frequents the site might know it" questions, and those ones don't get touched for days or weeks (if ever). Those questions don't seem to require references because the knowledge is either gained through practical experience (how to perform some bench work, or how to get an enzyme to operate at peak efficiency) or there aren't references to be easily found (what does DNA sequence XYZ on the banana plant's genome code for?).</p>

<p>Maybe there could be a checkbox while the asker is writing the question? At the end have a little:</p>

<p><strong>[X] Would you prefer references from academic or scientific knowledge-bases in potential answers?</strong></p>

<p>Then just add a bolded section in the reply form or in the answer itself to encourage citations for the people that want them.</p>
 540: <p>When dealing with specific questions relating to areas of currently active research, questions regarding concepts which are easy to assign to a research area with frequent publications, it is of course very difficult to defend refusing to provide references. When someone asks, "do mutations of the gene ABC1 lead to cancer?", the answer is, in the procedural sense, trivial: You look for research examining ABC1 vs. cancer, either the research says yes, no, or maybe, or there is no research on ABC1 and the answer is we don't know.</p>

<p>However that still leaves classes of questions pertaining to biology, which are interesting and not common knowledge, but would not be answered directly by literature:</p>

<ul>
<li>Answering a question may require taking several different given research findings, putting them together and making deductions from there. In this case you will have references for the premises, but your conclusion (and the correctness of your reasoning), which is the answer to your question, will not necessarily be confirmed by any publication (it may be that the question happens to be something few scientists would bother to publish on, because answering it takes so much effort compared to the career benefits).</li>
<li>The question may be too broadly scoped and interdisciplinary for a publication to deal with it. It may ask for synthesis of disciplines or fields which are just not combined very often by actual scientists.</li>
</ul>

<p>While it is nice to have sources and it is a bad habit not to give sources for your claims, I think it wouldn't be too shocking to ask you to accept that the scientific community is not exactly objective, fair and impartial with regard to what science it prefers to do. I mean this in the sense that, out of all the questions and unexplained phenomena to which the scientific method is applicable (and for studying which experimental methods exist or can be feasibly devised), individual scientists as well as the community as a whole, will be more likely to research some and not others. One reason is that any scientific research project is done by human beings with careers to worry about (and it seems increasingly so as time passes and costs of research as well as the dependence on cooperation from the rest of the community and governments/funding agencies are growing), and they will at some point ask the question, "is doing this research worth the effort, time and money? Is that expenditure of effort, time and money something that I can afford, considering how many papers and cites I'll get out of it?"</p>

<p>Human curiosity, on the other hand, is at least relatively neutral - it doesn't really matter how complicated, useful, or career-friendly a question is for us to become curious about its answer.</p>

<p>This site (I assume) is meant to address the latter, rather than the former, and as such there will be times when a question is asked and finding sources is challenging. Therefore, naively expecting every answer to have sources would be quixotic. I think it would be more realistic to treat it as a guideline rather than a rule, with the caveat that "answers without sources are allowed, <em>but you better have good reasons for not giving sources (and explaining those reason in the answer doesn't hurt)</em>". The latter part, requiring an explanation for why sources are eschewed when they are, might resolve the whole problem entirely, in fact.</p>
 67: <p>To be frank, no. While I think citations make <em>some</em> answers better, and requests for citations are always welcome, I essentially don't participate in Skeptics because I find it's approach to things extremely tiresome. If Biology followed suit, I'd cease to participate here as well.</p>

<p>One can, of course, disagree with that. But I spend far too much time working on how findings are published and cited to have much faith that a single link to an arbitrary paper renders an assertion nearly as solid as Skeptics seems to believe it does.</p>
 69: <p>I personally like to see claims referenced thoroughly; I do tend to downvote answers that make abstract claims without reference and have applied the <em>Citation Needed</em> banner on a few previous occasions.</p>
<p>Having confidently said that, I had a quick look through my own answers and found <a href="https://biology.stackexchange.com/a/451/69">this</a>, which probably neatly falls into the categories that you describe above.  I think we should be careful, therefore, to limit our discussion to the problem rather than any user in particular.</p>
<p>Overall, I think I agree with Nico and LanceLafontaine that this <strong>is</strong> becoming a problem and we should set standards early on.</p>
<p>At present, until the community verifies that this isn't best practice and we get a full strategy in place, I'd reccomend that unreferenced material be:</p>
<ol>
<li>Downvoted</li>
<li>Left a comment asking to add references</li>
<li>If particularly bad, flagged for moderator attention to get the notice added.</li>
</ol>
<p>This does lead to the next question, <strong>what to do with answers that have been given notice but not improved over weeks</strong>.  For example <em>all</em> of these <a href="https://biology.stackexchange.com/search?q=hasnotice:1">noticed posts</a>.  I'm rather hoping that other posts have taken the feedback on board, added references and had the banner removed, not entirely sure though.  I'm not sure whether they should be deleted as I feel downvotes would be more appropriate however some <a href="https://biology.stackexchange.com/a/916/69">extremely tenuous claims</a> have got fair scores.</p>
<p>Suggestions for all would be really well received!</p>
