How is the site policy on content-editing other people's answer?

Question

The accepted answer to this question suggests that community wiki is deemed sort of a legacy feature that serves no real purpose anymore, as people are supposed to just edit additional information into existing answers, if they feel that a given answer is good but is missing "something".

Both, Jigg and Pete L. Clark remark that this in practice basically never happens (essentially all edits are just grammar or spelling fixes, with the occasional do-over for clarity and style). This is also my impression - I have been reasonably active on the site in the last few months, and from the top of my head I cannot remember a single case where I have seen an edit that actually added content to an existing answer. Personally speaking, I would also see this as highly inappropriate, as there is no guarantee that the original author even endorses a given change. Pete L. Clark goes into detail in his answer why people seem reluctant to do anything but minor style edits to other people's answers.

My question is now as follows:

If we encounter a question that already has one or more answers that we consider really good, but we feel some minor-ish detail needs to be added. What is the right way to do it?

1. Post a comment and ask the original author to edit it in.
2. Edit it in directly.
3. Provide a new answer, which starts with something along the lines of "The existing answer by XY is good, but ...". I have done something similar myself today.

Option 1 is ok but cumbersome. The question linked at the top seems to suggest to me option 2, but how do we guarantee that the original author even has the same opinion on the topic? Option 3 seems to be the common way how it is currently done (my impression at least), but brings us close to community wiki territory.

Answer 1

I personally agree with the global SE policy on editing:

When should I edit posts?

Any time you see a post that needs improvement and are inclined to suggest an edit, you are welcome to do so. The original author of a question or answer may always edit their own post, regardless of reputation level.

Edits are expected to be substantial and to leave the post better than you found it. Common reasons for edits include:

• To fix grammar and spelling mistakes
• To clarify the meaning of the post (without changing that meaning)
• To include additional information only found in comments, so all of the information relevant to the post is contained in one place
• To correct minor mistakes or add updates as the post ages
• To add related resources or hyperlinks

Note that it is always clear when a post has been edited, and the edit history always shows who is responsible for the added content, so the "endorsement" problem should not really be one.

However, I'm not sure if the OP is always notified that an edit has been made on his/her post, if it's not the case, then it should be, to allow the OP to rollback the edit in case he/she disagrees with it.

That said, the option 3 is also completely acceptable, especially if the added content is substantial. I'm not sure how it brings us close to CW territory: CW only means that anybody with >100 rep can edit directly all posts, while a regular post requires users with <2K to suggest edits, which then need to be approved.

Answer 2

In the example you linked to for Option 3, that is actually the correct option to use. You are not editing their answer—because it's providing a new viewpoint that the other respondents missed. Moreover, it was a substantial answer in its own right, so doing what you did is exactly correct.

For smaller-scale edits—correcting facts, adding links or appropriate qualifying statements, and so on, either option 1 or 2 works, depending on your comfort level with editing posts directly or not. I personally use option 1 as the default, but that's in part because of having "privileged" status as a moderator.

Answer 3

If you would like an answer to contain additional detail, which you feel will likely be endorsed by the poster, but you are worried that they may not be notified or may not quite approve, one option is to edit the post directly and add a comment along the lines of

Good answer, XXX! I have added some detail on YYY because ZZZ, but of course feel free to roll it back.

This makes immediately visible to anyone that there's content that's been edited in, and what that content is. It also ensures the poster will get an inbox notification next time they log in, and I feel it is more polite than a blunt edit.

Of course, this still has disadvantages and should only be done if you really are only adding details to which the post's owner likely won't object.