Originally by Jimmy Wales, 16 May 2006 (Source):

I can NOT emphasize this enough.

There seems to be a terrible bias among some editors that some sort of random speculative "I heard it somewhere" pseudo information is to be tagged with a "needs a cite" tag. Wrong. It should be removed, aggressively, unless it can be sourced. This is true of all information, but it is particularly true of negative information about living persons.

I think a fair number of people need to be kicked out of the project just for being lousy writers. (This is not a policy statement, just a statement of attitude and frustration.)

Zero information is preferred to misleading or false information

(my emphasis)

While the above quote was in the context of misleading information with respect to living people, I believe its a good principle for all articles.

• Every Wikipedian should read Wikipedia:Verifiability.