Wikipedia:Try to verify

Try to verify is what editors do, naturally, to follow the Verifiability policy. This page also discusses the question of when to cite sources, which is another way of framing the question.

Executive summary

 * 1) When making contributions, provide a reference.
 * 2) If you see information that you believe needs a reference, your options include:
 * 3) Finding one (best)
 * 4) Failing that, either:
 * 5) Tagging with
 * 6) Moving unreferenced material to talk page with note asking for reference
 * 7) Asking editor who contributed material to provide a reference
 * 8) Removing the information

Depending on the circumstances, any of the options of the above may be best.

When to cite sources
'''Wikipedia articles should not use other Wikipedia articles as references. Wikilinks are not a substitute for citable sources.'''

Below are instances of best practices for assuming good faith while citing sources and avoiding original research.

When you add content
If you add any information to an article, particularly if it's contentious or likely to be challenged, you should supply a source. If you don't know how to format the citation, others will fix it for you. Simply provide any information you can on the source.

In general, even if you are writing from memory, you should actively search for authoritative references to cite. If you are writing from your own knowledge, then you should know enough to identify good references that the reader can consult on the subject &mdash; you will not be around forever to answer questions. The main point is to help the reader and other editors.

The need for citations is especially important when writing about the opinions held on a particular issue. Avoid weasel words such as, "Some people say&hellip;" Instead, make your writing verifiable: find a specific person or group who holds that opinion, mention them by name, and give a citation to some place where they can be seen or heard expressing that opinion. Remember that Wikipedia is not a place for expressing your opinions or for original research.

Because this is the English Wikipedia, English-language sources should be given whenever possible, and should always be used in preference to foreign-language sources of equal calibre. However, do give foreign-language references where appropriate. If quoting from a foreign-language source, an English translation should be given with the original-language quote beside it.

When you verify content
You can add sources even for material you didn't write if you use a source to verify that material. Adding citations to an article is an excellent way to contribute to Wikipedia. See Forum for Encyclopedic Standards and WikiProject Fact and Reference Check for organized efforts to do this. Direct quotes, used as a method of easing factual verification, can be provided (in whatever format is agreed on by the main editors of the article) for any statement.

When there is a factual dispute
Disputed edits can be removed immediately, removed and placed on the talk page for discussion, or where the edit is harmless but you dispute it and feel a citation is appropriate, you can place citation needed after the relevant passage. This should be used sparingly; Wikipedia has a lot of undercited articles, and inserting many instances of citation needed is unlikely to be beneficial. The template cite check can be useful for flagging quotations taken out of context and other misuse of citations.

When there is no factual dispute
Think ahead: Try to imagine whether people might doubt what you wrote or need more information. Supporting what is written in Wikipedia by referring to a clear and reliable source will add stability to your contribution.

Examples of editing scenarios
A way to think of the above options:

The ascending scale of doubt over accuracy, neutrality etc:
 * 1) (least doubt): leave it
 * 2) Ask for reference on talk page
 * 3) Tag with   or remove to talk page
 * 4) (certain that it's rubbish) Remove totally

Step 5 would be reserved effectively for vandalism, bad jokes, and other nonsense.