Why are answers deleted?

Question

Answers may be deleted by the moderators, for various reasons:

• Some reasons are obvious to everyone (e.g. spam)
• Some reasons are obvious to the regulars of this site (e.g. no references)
• Some reasons are less obvious (e.g. insufficiently good reference; or a conclusion that's not supported by the referenced evidence; or etc.)

There are FAQs, which include FAQ: What makes an answer good on Skeptics.SE?

It might be useful to list here the various reasons (categories) for why an answer may be deleted:

• Because the reasons (rules) aren't listed in one place elsewhere
• Because the reasons can't be inferred by users (because users can't see all previously-deleted topics nor understand why they were deleted)
• Because it's a source of controversy and unwitting ill-will ("why was my post deleted?")

Please post a separate answer for each reason, with one answer for each reason.

Answer 1

It occurs to me that one way to answer this, is to consult the informal AutoReviewComments template I use for handling the most common problems I see.

This isn't an exhaustive list, but just the ones I find I am typing so much it is worth automating.

No references.

As discussed in another answer, this is not an instant delete, but starts the stopwatch.

Should be a comment.

For short anecdotes/opinions/clarifications/etc posted by new users who don't have the rep to comment. Answer is converted into a comment.

Anecdote

If the answer relies on a personal anecdote, it is deleted with instructions on how to improve it.

Theoretical answer

If the answer is built entirely on personal speculative predictions, rather than empirical data, it would be deleted.

Pure Opinion

If the answer is purely based on what you think of Obama, it is deleted with an explanation of how we differ from a forum.

Trolling

I added this template recently, and I am still experimenting with whether it is successful. We see some answers that are just trying to get a rise out of the poster. I explain how quickly their pearls can be deleted, and invite them to contribute better, or else they'll be banned.

Answer 2

I suggest the following as a preliminary list of reasons:

1. No references at all
2. Quality of the reference is "relatively poor", i.e. is no better than the qualify of the reference which contains the notable claim cited in the question: e.g. using published newspaper article as a reference is OK if the question was about a mere rumour, but is not OK (is inadequate) if the claim that's in doubt was carried in a different newspaper: the reference in an answer should be (relatively) higher quality than the reference (if any) in the question.
3. Quality of the reference is "absolutely poor", e.g. it's a link to your own blog, or a repeat of the reference in the question
4. Author's conclusion is stronger than the reference supports (your conclusion/summary should not be more emphatic/conclusive that supported by the referenced evidence)
5. Original research (experiments you conducted at home)
6. Unjustified arithmetic (pulling numbers out of a hat)
7. Not answering the question (being off-topic)
8. Repeating an existing answer

Answer 3

(Sorry for not following the suggested format. If this question eventually gets turned into a FAQ, we can clean all this up.)

There is an existing FAQ item tackles many of the same issues as this question, but from another direction - it explains it as a process, rather than a set of triggers: Guidelines for Inadequately Referenced Answers

From that list we can see some of the items in @ChrisW's answer aren't quite that simple.

"No references at all", for example, has a process of requesting references associated with it. A more accurate description is that a question is deleted when:

• No, or inappropriate, references, AND
• a week has gone by since the user/community was asked to fix it OR the user directly refuses to reference it, AND
• it comes to a moderator's attention (including via a flag), OR it is one of our very, very occasional sweeps of the oldest unreferenced answers in which we rarely get as far as answers as recent as 12-months-old.

(Putting it this way probably isn't the clearest approach. If this is unclear, and what we already have is unclear, is there a third approach?)

Those guidelines similarly addresses our approach to original research (which, the recent definitional post suggests, subsumes unjustified arithmetic).

"Not answering the question" tends to be flagged - it is a bit like spam. It is just an unwanted answer. (Spam and deliberate vandalism is more likely to result in a permanent ban rather than just deleting the answer with an explanation.)

Repeating an answer is fine - especially if it is better argued and may earn more upvotes.

(I personally prefer to copy-edit someone else's question to make it better, and let them get the rep for the research part. However, I am not in a position of scratching for enough rep to post comments; I am motivated to have trusted users taking on some of the self-policing roles. I can understand someone preferring to earn their own rep with their own answer.)