Give an incentive for finding duplicate questions [duplicate]

Question

At present if you see a question that may be a duplicate and has an easy answer you can post the answers or post a link to the duplicate question. (Or the few hi-rep users can vote to close it as duplicate, think of normal users here, not the people that read Meta)

It is better for Stack Overflow if a link to the duplicate is posted as a comment, or the user votes to close the question as a duplicate. However, the user gets more rep if he/she posts the easy answer quickly.

I'm thinking of something along the lines of:

• First person to post a comment that points to possible duplicate gets some rep if the question is closed as a duplicate and at least 2 of the other closers chose that same dupe question.

• Whenever someone votes to close as a duplicate, a “possible duplicate” comment should be posted with a link to the other question, if there is not already a link to it in a comments. (The system now does this)

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As Ether said, The removal of reputation earned from answering a question that is later closed as a duplicate would at least remove the negative incentive, but is that enough to correct this behaviour?

Is a “duplicate finder” badge part of the solution?

• A bronze badge for being the first person to vote to close a question as a duplicate with the same “duplicate of” question chosen as most closers choose.
• A silver badge for doing the same 25 times.

See also Dr. Strangedupe: Or, How I Learned to Stop Worrying And Love Duplication

Improve tools for closing as duplicate, would also help.

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Now that the duplicate can be marked by the OP as helpful, we have another trigger to consider for awarding badges and/or rep.

Answer 1

I'd also like to see the removal of reputation earned from answering a question that is later closed as a duplicate. Currently there is little incentive to post an answer on the original question (or merely post a link to the original), rather than re-answering the question. It's tiresome seeing the same answers again and again, and seeing this behaviour awarded with reputation.

Answer 2

I'm reviving this thread because I'm surprised there's no badge offered for this. Looking for duplicates requires more effort than other types of close vote and we're always saying that badges should be encouraging positive behaviour on the sites.

I propose the following badges:

Seeker - First question closed as a duplicate of another question you found.

Scout - 50 questions closed as a duplicate of another question you found.

Reconnoiterer - 200 questions closed as a duplicate of another question you found.

The underlying criteria would require at least 3 of the total close votes to concur with the found duplicate. Reconnoiterer could possibly be a repeatable to encourage continued behaviour. I can't see any "gaming" issues arising from this, because it requires agreement from other members of the community.

Clarification: "found" equates to finding a duplicate and casting a vote to close on that duplicate, or flagged for review with the appropriate duplicate chosen.

Answer 3

I'm wondering if it doesn't make sense to lower the reputation threshold to vote to close as a duplicate. Unlike other votes to close, there is already a bit of a check on this; you have to actually point out which question this is a duplicate of. That discourages (at least a little) people from doing it casually. So unlike "subjective and argumentative," where it's really a matter of opinion, and makes sense to restrict to higher reputation users, it would be good to have more participants in fighting duplicate questions.

Regarding your second point, the site already marks questions as possible duplicates after a certain number of votes. Perhaps it could do so (less intrusively, maybe) after the first vote?

Answer 4

Send us a package of cookies for every 100 duplicates we vote as duplicate.

No rep gaming issues, no badge gaming issues, no problem!

Answer 5

I am all for rewarding closevotes (not only finding duplicates). If reputation

is a rough measurement of how much the community trusts you; it is earned by convincing your peers that you know what you’re talking about.

it is illogical that only answering increases reputation but closevoting doesnt. If I supply a closevote and people follow it, I have effectively convinced them that I know what I am talking about, too - namely that a particular question should rather be closed than answered.

Moreover, even if a question is closed, it will usually have received some answers before. The reputation gained on these remains unless the question is deleted. Deletion rarely happens due to the 20k requirement. But if it remains it implies they gained trust, while those that closevoted dont gain anything at all, although they did the right thing and those that answered did the discouraged thing.

So if reputation really is a measure of community trust, closevoting should gain reputation as well. This is true for all the additional privileges gained. If we want more people to use them, we have to reward them for it. Currently, the only reason why a 3k+ user would closevote is because s/he understands the necessity of it. Unfortunately, there is even a lot of high rep users who dont see that and repwhore on whatever they can answer. Are those really the people we trust?

Regarding the problem of incorrect closing I am quite sure that this is only a minor issue. I've seen far more correctly closed questions than reopened ones. The few false positives could be further mitigated by allowing to uv/dv on the votes instead, e.g. cast a closevote and have people vote it up or down until a threshold is reached. +5 will close, -5 will fade the vote. And allow people to revoke their vote please.

Regarding rewarding and badges, I dont see why we cannot have both. Someone who continuely does her/his community duty and closevotes should be rewarded for it with a badge or two. Badges are not enough to encourage closevoting though, because once you got the badges, you dont have an incentive to closevote anymore. So we also need some reputation gain.

Answer 6

Another possible solution might be to separate the problems of flagging duplicates and voting to close the duplicates. What if anyone (or almost anyone) could flag a duplicate using the functionality presently built into "close as duplicate?" Then "close as duplicate" would be enabled for higher reputation users once the first duplicate has been flagged.

Answer 7

This is a terrible idea. There, let me be the first to put in a negative answer.

I have had to reopen some questions because not all SOpedians are as smart as the next bloke. They see some similar words, and think it must be a duplicate.

There also seems to be some moths that are driven to brackets around Close(n) and see their call of civic duty to blindly follow where others have gone before.

Similar to my advocating against this: Should the sportsmanship badge be awarded multiple times?, I'd like some hard numbers for % of questions actually closed as duplicates.

Let's say theoretically

0.1% closed as duplicates
0.12% failed attempts to close
0.016% reopened
no badges

I reckon you will see the close/reopen buckets both increase significantly (more towards close since it is incentive-ised) and failed attempts go through. My reasoning is simple - human nature. Just as people will cast votes for opposing answers for a week and never again for sportsmanship and vote solidly for another 17 days^* after for electorate (and also thereafter rarely vote again).

^*If you don't believe me, just go to https://stackoverflow.com/users?tab=voters They stick out like a sore thumb with votes an exact multiple of 30.
_{Disclosure: I'm guilty too, but I actually continue voting as much because I do really read that many questions!}

Answer 8

The trick is to find a system that only rewards work. My proposal:

• When (say) 5 people have identified a question x as a duplicate of question y, award rep to those 5 people and close the question.
• Don't reveal which questions have been suggested as duplicates before a question is closed.

The 2nd point is important to avoid triggering a close-as-dupe epidemic. It means that people individually have to do the work (searching for dupes) to get the rep. You have to be fast (otherwise 5 other people will get there first), and you have to be right (pick the dupe that others picked).

Inspired by: The ESP Game from Games With A Purpose (from about 22:30 onwards, though it's all fascinating stuff!)

Thoughts? Are there ways that this system could be abused?

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UPDATE 2/5/2012: Eliminating Cheating

Jeff's comment raises a valid concern that people could easily game this system by voting to close a question as a dupe and then writing a comment mentioning the other dupe; others will then vote to close as the same question. I can see this happening because there's positive feedback at work here -- both the original comment-writer and subsequent close-voters stand to make some quick rep. But I think I now have a solution to that:

To prevent people "dropping hints" about dupe-parents in comments/answers, you could simply forbid people from both identifying a question as a dupe and commenting on or answering that same question -- i.e. as soon as you do one, you can't do the other(s).

Think about it: if you see a question and immediately recognise it as a dupe of something else, there's no need to comment on/answer it. The only scenario I can think of where this might be too hard-line is when someone uses a comment to ask for clarification, and only recognises the question as a dupe after receiving that clarification, but this would be pretty rare. In the unlikely event that this turned out to be a common problem, the system could just be changed to waive the restriction for users above $SOME_THRESHOLD_REP.

Answer 9

Not sure this is a great idea. On the surface it sounds interesting, but often times people simply skim the question and then vote to close not realizing that there are differences in the questions. It then is much harder to get the question reopened and basically an uphill battle.

Answer 10

You might be interested in my script Duplicate Question Suggestion Boxes which makes this more easy.

An example of its effectiveness, where otherwise the link would be hidden somewhere in the side bar:

Of course, we can't enable this for all users.

Answer 11

The key to any community-based, "Duplicate Task Force" is opening and simplifying the process.

First, provide 1k+ rep users with a "flag as duplicate" option, which will allow for a single link to be provided. This makes it easy and painless to report.

Display the flag and the duplicates found to the asker (and others? Debatable.). This makes the process open, and will help the asker.

Then, facilitate moderators' (or 10k+ rep users') job by providing them with a list of duplicate-flagged questions. Allow sorting by number of duplicates found. This makes the process manageable.

Finally, provide the users who flagged the question with one duplicate or another (it's not a game to get the right one) with a small incentive. Lock down rewarding after question has been closed as duplicate. That makes finding duplicates rewarding.

Answer 12

For new users, few questions are duplicate. Both new answerers and new askers get frustrated when they are trying to do the right thing, but it gets closed as a duplicate. Their initial reaction is not: "Thanks for pointing me to the right question", but: "Why are you rudely interrupting my conversation?"

The irony is that the old users enjoyed the very same thing they are denying to the new users. With the very same questions, and the very same answers: the only difference is the timestamp on the question.

Even more irony is that most high-reputation users got high reputation by answering questions instantly. The fact that they can answer instantly is a strong indicator that the question has been asked before, and is on the top of their tongue. In other words: most high reputation users are very good at answering duplicates.

At the end of the day, the fact that only a small number of duplicates gets closed means its not a big problem. But until duplicates are closed in a socially acceptable way, I think it would be a very bad idea to reward or even encourage more duplicate closes.

Answer 13

We should just give a badge for 'Closing as Duplicate' enough times (when it's the confirmed close reason). I do not want to disincentivize good answers even to duplicate questions. All questions deserve good answers.

Answer 14

I think this is a great idea. Especially the "duplicate finder" badge. It has been argued that this may require a feature to mark duplicates, but that may not be needed. Anyone who has sufficient privileges to add comments can add the link to the duplicate in a comment. If the question is closed, the Stack Overflow engine can harvest the URL, and award a badge to the user who was the first to link the question with the duplicate, albeit through a comment, or through a close vote.

Some of the other answers argue that questions are closed as duplicates, where the question is not actually a duplicate. This is true. And this may happen more often if duplicate finding is encouraged.

But this is not a problem.

If the person asking the question disagrees, she can always compose a better documented question, referring to the other questions, and point out why her question is not a duplicate. I don't expect this to happen more than a few times in every hundred duplicates, so we should not worry that this will flood the site with more duplicates.

Answer 15

I know its tiresome to see duplicate questions but I am guilty of this as it is sometimes hard to find the duplicate in the sea of questions. I wanted to ask a question about deleting my own posted question, I did a search for this and came up with 50 pages of questions with the same search parameters. I looked at the first few pages...but this got me thinking that sometimes users post duplicates because they need the answer but don't want to search through the sea of questions as this would take more time than posting a question. I like the idea of rewarding the finding of a duplicate to the first person who finds it then it gets put up to vote and if enough votes agree then it gets merged into the old question answer.

Answer 16

One way to incentivize finding duplicate questions would be to make it easier to find them. A tab could be added to the review section for "Possible Duplicates".

When you type in the title for a new question, you see "Questions that may already have your answer". The functionality that creates that list could be adapted.

New questions that meet a certain threshold of commonality with existing questions could be shown along with the list of "Questions that may already have your answer" that met the threshold.

Answer 17

I think that a combined approach would be the best solution.

Andy E's badge suggestion looks promising, but I think it would be much more effective when combined with removing rep earned by answering dups as Ester suggested and possibly even awarding some small amount of rep for successfully closed dups like Gordon suggested.

Above and beyond these measures I suggest:

• Making the Related Posts column visible in the First Posts Review queue, so that obvious duplicates stand out and can hopefully be caught as a part of the review process.

• Adding "asking too many duplicate questions" to the list of reasons that one could be question banned, even if those duplicates have not been deleted.

Note:
Apparently there's no way to find out whether asking an excessive amount of duplicate questions is currently taken into account in the auto-ban equation. If they are please disregard.

Answer 18

I have some ideas for gamifying the process instead of just giving rep incentives and would like to know where the potential holes are for promoting exploitation of badges/reputation. Each one of these suggestions have the goals of:

1. Reduce existing duplicates that have not yet been identified
2. Reduce rep-hunting against low-hanging dupe-fruit
3. Identify users who answer duplicates

I don't like the idea of awarding reputation points for these kinds of things, but I also know that reputation is a valuable metric to many users, so many of these potential suggestions are more geared towards badges than rep.

Tackling #1

New Badges

Potential Name: Death by a thousand cuts || Hirudotherapist
Purpose: A hard-to-achieve badge to encourage dupe-hunting
Tiers: 1; metal-grade, flexible (probably gold)
Unlocked with: 1,000 questions closed as duplicates by actions of the user
Rationale: Whether they're normal users or moderators, this is something that can be worked towards over time to better the site(s).

Potential Name: Justice never sleeps || Mold-Hunter
Purpose: Cleaning out the old dupes that snuck past us already
Tiers: 3, threshold values flexible
Bronze Tier 1 Unlocked with: 1 question closed as duplicate by actions of the user for a question older than 6 months
Silver Tier 2 Unlocked with: 25 questions closed as duplicate by actions of the user for a question older than 6 months
Gold Tier 3 Unlocked with: 500 questions closed as duplicate by actions of the user for a question older than 6 months
Rationale: Even old dupes can hurt. If we encourage badge-hunters to start from the back and work their way up, it could have the nice effect of not overlapping badge-hunters with users just trying to do the right thing as they come across them.

My hope with these two badges is that anyone looking to do badge-hunting with these will try to tackle both the backlog of dupes while not completely ignoring incoming dupes.

Also, with the thresholds being so high, the more people that participate will make it harder to achieve them, making these eventually a sort of status-symbol badge for those who threw themselves to the task, first.

Tackling #2

I'm not sure what all is in place for #2, so these are less concrete gamifications than conceptual musings.

Rep Changes

Are we already taking away earned reputation from upvoted answers to questions closed as duplicates? If not, I think we should revisit the idea. This is a very straight-forward way to stop #2, but I admit that it is quite rep-invasive. Maybe a 24-48 hour window for losing rep while an alternative addresses potential dupes in that window.

The alternative might be to freeze rep-acquisition for all answers as soon as the question is flagged as a potential duplicate; this would be invisible to most users until actually marked as a duplicate, if I understand it correctly. Upvotes would still "count" but the user getting the upvote only gets the rep if the flag ends up not being accurate.

Another potential dupe penalty if not already enforced is decrementing the tag's badge score increase when the question is closed as a dupe. I'm pretty sure that only applies to accepted answers, but the psychological price would still be there.

With or without rep changes, I think next badge can might help with #2

New Badge

I'm a big fan of this next badge, as it rewards casual and hardcore reviewers with different tiers with timing and quantity instead of just quantity. I think it's a potential candidate for a new set of badges across SE regardless of how you feel about the rest of my suggestions.

Potential Name: Quick-Draw || The Fastest Gun in the West
Purpose: Reduce new duplicates, encourage review-queues, encourage experienced/knowledgeable users to find existing answers instead of re-answering them
Tiers: 3, threshold values flexible
Bronze Tier Unlocked with: 1 question closed as duplicate by actions of the user for a question less than 6 hours old
Silver Tier Unlocked with: 100 questions closed as duplicate by actions of the user for a question less than 3 hours old
Gold Tier Unlocked with: 1,000 questions closed as duplicate by actions of the user for a question less than 1 hour old

Tackling #3

New Badge

Potential Name: Good Intentions || Paving the Road to Hell || Doh!
Purpose: Identify users capitalizing on answering dupes while not exactly calling them dunces, rep-moochers, or menaces
Tiers: 1, a new one each time it occurs
Bronze Tier Unlocked with: Had an accepted (and/or up-voted) answer for a question that was closed as a duplicate
Rationale: An accepted answer to even a duplicate question added value somewhere, but not the kind of value that SE wants to encourage. The more badges a person has of this, the more that it will stick out by sheer count compared to other badges for people that make a habit of doing this kind of rep-hunting against low-hanging fruit likely already addressed in another question

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I'd like to point out or at least disclose that I have a bad habit of doing #3; I never do it on purpose, but knowing that I would be getting something like this would encourage me to look for existing answers even more thoroughly instead of blindly answering something that I know off-hand.

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Some might be asking why the emphasis on people contributing to dupes and dupe-hunting instead of penalizing the people writing the dupes in the first place. My rationale is this: getting downvoted and your question closed is fairly demoralizing as it is. It has happened to me several times, and each time it does I get more encouraged to research further before asking. I really don't think this aspect of tackling dupes can be improved by much, as the Similar Question mechanic when writing out a new question I feel works fairly well, at least for me.

Answer 19

We could implement this in much the same way as the vote to close system. A user could submit an "answer" that is somehow marking this question as a duplicate and all other users could see it, and respectively vote if it really is a duplicate. 5 votes closes the question, and maybe gives -5 rep to the asker (seems fair to me if they can't search).

Answer 20

Count me in on the idea to reward for finding duplicates.

Though I suggest to instead reward with reputation rather than a badge (rationale follows):

• Upon closing a question as a duplicate, award N rep (see below for considerations regarding the amount) to the user who first suggested the duplicate
• The rep is retracted if the question is later reopened
• Does not apply to own questions
• Does not apply to closures that aren't subject to peer review (by mods/golden badge holders)
• Discussable: what to do with the normal accept mark:
  • count as well
  • forbid/delete (the duplicate takes precedence)
  • retract the rep for the duplicate if present (normal acceptance mark takes precedence)

Rationale

• The user who found the duplicate essentially answered the question
• This will eliminate the current ill motivation to re-answer: re-answering (incorrect/suboptimal course of action) yields reputation while finding a duplicate (correct course of action) doesn't
• The incentive to game the system is limited by the fact the reward is limited to just the amount awarded at closure

Downsides

• the OP does not participate in the award, thus it violates the principle that "acceptance means it has helped the OP the most"
  • not necessarily: if the OP did not protest the marking, this means they are satisfied with the "answer"
• allows users to conspire by intentionally asking duplicates, akin to upvoting rings (this is nothing new but it means the algorithms will have to be adjusted)
• allows rep-whores to spam "looks similar" suggestions hoping that voters overlook the differences. This would also be cluttering the already overloaded Close review queue (again, statistical analysis will have to be updated to detect and stop this pattern).
• escalates (as it exists already) a flavor of the Fastest Gun in the West Problem - once a question is closed, it's nign-impossible to re-open and re-close it with another reason - e.g. if a more fitting suggestion arrives.
  • Even the official position is that if a question is closed, and shall stay closed, it should not be reopened even if the reason currently stated is not the most appropriate one (anymore).
  • this may be solved by treating duplicate suggestions as answers to some degree: e.g. a preferred one could be selected by an OP. I'm not the first one to get this idea: Show duplicate suggestions as answers .

Considerations regarding the amount

• Finding a duplicate is a noticeable to significant amount of work, but still less than composing an own answer.
  • On the other hand, the closure cannot bring further rep from upvotes.
  • Still, answers to duplicates bring little rep as a rule
• The reward amount shall make duplicate searching be seen as an easier course of action than re-answering reward/work ratio-wise. Still not much enough to justify aggressive "partial-duplicate" spamming hoping that voters will overlook the differences.

If not 15, maybe 12 rep will be seen adequate (note the word "seen"). 10 appears too little already - answering a question straight is more than just "being useful".

Answer 21

This answer is more for consideration purposes if/when implementing this feature-request:

1. The binding vote-to-close (and re-open) for gold tag-badge holders should be considered here. For now questions closed as a duplicate (or re-opened after being closed) may be excluded from any consideration for badge-worthiness.

   There is distinct difference between how Stack Overflow is hammered with close votes in comparison to other network sites. So this may be a non-issue to start with. After all, tag gold badge users are considered trusted in that "field".

2. Another thing to consider is how mods are affected by finding (obvious) duplicates. As they possess the ultimate dupe-hammer, they may never be able to attain these badges.

Answer 22

I'd rather give badges if the duplicate was marked by the OP as helpful – as you probably know, when you suggest a duplicate, the OP can mark it as helpful or editing the post to explain why it is different. This makes sure that people won't suggest harmful duplicates as they wouldn't be rewarded anyway. I'd rather not give rep.

I suggest the badges:

bronze – 1 duplicate accepted by the OP

silver – 25 duplicates accepted by the OP

gold – 100 duplicates accepted by the OP

Badge names are all over the post. I don't have an original suggestion for them.

Answer 23

I was looking at Show duplicate suggestions as answers . I think if the candidate duplicate is offered as an answer, then the person that posted this should get rep credit for people that upvote this "duplicate" answer. Possibly the finder gets 2 points of rep per upvote, and the author of the original answer gets 3 points of rep per upvote. This should be a strong incentive for identifying a duplicate.

Once a question has been determined to be a duplicate, all the provided answers should be deleted, leaving only the duplicate answer candidates. That would remove the rep gained from providing a new answer to a duplicate question. This should be a strong disincentive for answering a question that is likely duplicate.

Answer 24

Maybe you could add "flag as possible duplicate" as a top-level option in the flag-moderator box? (with a requirement for a link).

That makes it more obvious promoting it happening more, and opens it up to lower-rep people to flag as possible duplicate, without directly voting for duplicate.

Answer 25

I'm very much in favor of awarding rep to those who post links to previous answers to the duplicate question. I'm less in favor of giving rewards to simply flagging questions as a duplicate.