Codidact supports duplicate suggestions and hold suggestions. Duplicates are not a type of hold -- the focus of a duplicate is "get to an answer more quickly" and link posts together, while hold is more about closing a question down until problems are addressed. We think the user experience of duplicates can be improved if they're not treated as closures/holds.

Duplicates are, intentionally, more "democratic"; while holds require the Curate ability, anybody with Participate Generally can participate in duplicate resolutions.

Suggesting a duplicate

Anybody with the Participate Generally ability can propose that a top-level post is a duplicate of another top-level post in the same community. (This could be a different category.) This spec also covers "superseded" or other duplicate-like phrasings -- the behavior is the same, even if a community customizes its wording.

To suggest a duplicate, any user (with the ability) can:

• select the Tools menu under the post
• select "suggest duplicate" from the menu (move "close" to this menu at the same time to reduce confusion)
• fill out an in-page form with a required link and an optional comment (the comment can be helpful when it's not obvious why the other question is a duplicate)

Question: Should we disable the option if you have a suggestion pending, i.e. one suggestion per user at a time?

On submission:

• A "Possible duplicate" comment thread is created or updated. A comment is added with the link and (if provided) additional comment. These comments are attributed (duplicate suggestions are not anonymous).
• If there are now enough votes for the same duplicate target ("enough" to be defined), the question is marked as a duplicate. The author receives an inbox notification.
• Otherwise, we display a notice of the suggested dupe, including links to the target and the comment thread, with action buttons (see below).
• The author and everybody who has already answered the question receive inbox notifications of suggested duplicates.
• State changes (marking a question as a duplicate or reversing it) are recorded in the post history.

Notice and actions

The notice is something like the following:

This question might be a duplicate of (other title with link) (could be multiple).
Community members provided the following feedback: (comment text that accompanied votes, unsigned here, and link to thread)

The author additionally sees:

Please read the linked question and its answers. If your question is different, you can edit to clarify.

And two buttons: "Yes, it's a duplicate" and "No, I will edit". See "author response" for how these buttons are handled.

Question: Should there be a third option, for "no, I disagree and don't need to edit" (spurious suggestions, etc), which would be treated as an ordinary "disagree" vote?

Everybody else who has Participate Generally sees two buttons next to each suggested duplicate: "agree" and "disagree". Choosing either prompts for a comment to add to the thread (like the initial suggestion).

Question: should each dupe suggestion show the number of suggest + agree / disagree tallies? Or should people who want to know the details have to go to the comment thread?

Answering a possible duplicate

While duplicate suggestions are pending, starting an answer generates a "hey, this might be a duplicate" alert, form and wording to be determined. This serves two purposes: (a) if you know enough to answer the question you probably know enough to contribute to the evaluation of whether it's a duplicate, and (b) you might want to answer that other question instead (or in addition).

Author response

If the author agrees it's a duplicate, the question is so marked (author's vote is binding). A notice is added and "[duplicate]" is added to the title. If there are multiple suggestions, the author selects one or more.

If the author disagrees and begins an edit (either via the button or the usual way):

• It's the usual edit interface, except that "My question is not a duplicate of (link) because" has been inserted at the bottom and (ideally) the cursor is positioned there. If there's more than one dupe suggestion, do this for each and position cursor at the first.

• If the author has the Edit ability, when the author submits the edit, the duplicate notice is removed from the question (for all viewers) and this review/resolution is logged in the history. (We can talk about yo-yo cases, where the author keeps rejecting duplicate votes this way, but I think it's something we should consider later. Let's not over-complicate it to start. Perhaps we only allow one author-edit resolution per question.)

• If the author does not yet have the Edit ability, the duplicate notice remains and is updated to add a message along the lines of "thanks for your edit; the community will review to see if it's not a dupe any more" (not those words). The community sees something like "the author edited this post in response to duplicate suggestions" and, for those who can review edits, an invitation to do so.

Review: problem solved?

Users who can review edits see a notice on the post (similar to the "suggested edit pending" one) that says something like: "This question was suggested as a duplicate of (link) and the author has edited to address the suggestion. (review button)".

Entering the review shows the diff (like for a suggested edit) and includes a link to each suggested duplicate.

The options for the review are "Not a duplicate" and "Still a duplicate".

• Choosing "still a duplicate" prompts for a comment and is treated like a duplicate vote. If there are multiple duplicate suggestions, the reviewer checks off which ones apply (maybe it's not a dupe of A any more but still is of B).

• Choosing "not a duplicate" resolves the suggestions -- the question is reset to its "ordinary" state, with the resolution being logged in the post history, and the "possible duplicate" comment thread is archived. (Subsequent duplicate suggestions start over with a new thread.)

Reopening

If a post was marked as a duplicate, everybody sees the duplicate notice. Those with the Participate Everywhere ability also get the "disagree" button, like when duplicate votes are still pending. Here the comment is required -- explain why the duplicate status should be removed. The comment is added to a "possibly not a duplicate" thread. The duplicate notice is updated to add something like:

This question might have been incorrectly marked as a duplicate. Community members provided the following feedback: (comment text, link to thread).

Unaddressed issues

• Retracting votes
• Third-party edit from someone trying to help -- how does that affect the flow?
• Vote threshold