Wikipedia has had a huge influence over the development of Stack Exchange. This is another instance where we steal page from Wikipedia's book. After all, why reinvent the wheel? 

The Wikipedia community relies on the **[No Original Research](http://en.wikipedia.org/wiki/Wikipedia:No_original_research)** core policy to combat unsubstantiated claims from finding their way into articles:

> ![Nutshell][1] 
> This page in a nutshell: Wikipedia does not publish original thought: all material in Wikipedia must be attributable to a reliable, published source. Articles may not contain any new analysis or synthesis of published material that serves to advance a position not clearly advanced by the sources.

The very purpose of this site, as defined by **[the FAQ](http://skeptics.stackexchange.com/faq)**, is to combat unsubstantiated claims:

> Skeptics - Stack Exchange is for skeptics, rationalists, free thinkers, or **anyone who questions pseudoscience.** Skeptics is about *applying* skepticism — it's for **researching the evidence behind the claims you hear or read.**

The voting system of Stack Exchange is largely meant to relax any need for specific policy regarding what constitutes a *valid* answer (and by and large it accomplishes this) — however, due to the *nature* of Skeptics, the community needs to enforce the idea of **no original research** to encourage healthy voting.

We **strongly encourage users to cite all significant claims** they make in their answers. Citations are not needed for basic science (around high school level), however.

There are some types of questions that we can safely answer without needing references such as claims that blatantly violate some laws of nature or known scientific facts. For example, debunking a claim about a perpetuum mobile, linking to Wikipedia's article about [the laws of thermodynamics][2] might be advisable, but that is only be a convenience for the readers, not a citation as such.

**Bad:** 

* "...since I have personally experienced it numerous times"
* "Anecdotally, I've seen it..."
* "I heard that it was also caused by ..."
* "I'm not sure if this idea comes from some research"

**Good:**

* "There is a fairly comprehensive article on the topic at..."
* "A recent Argonne National Lab study concluded that..."
* Even better, multiple sources


  [1]: http://upload.wikimedia.org/wikipedia/commons/c/ce/Nutshell.png
  [2]: http://en.wikipedia.org/wiki/Laws_of_thermodynamics