Does Stack Overflow have any mechanism to guard against "mutual" cheats?

I noticed that sometimes, when someone asks a stupid and easy-to-answer question, almostly instantly, a full, good answer from another user appears, which obviously receives a lot of upvotes from other users.

To me, it seems that this is possibly due to cooperation or collusion between the asker and answerer for rep gain. Not that they are upvoting each other, but that the answerer is a shill -- the answer was prepared in advance of the question being posted.

UPD: everybody, who thinks that it's not a problem, and all that we need - just downvote 'stupid' questions - please downvote this one for example: In a switch statement, why are all the cases being executed? Now I think it's not even ethic to answer such a questions and gain an easy rep... It is not what SO is supposed to be. Of course it's great for juniors and newbies, they instantly receive the feedback from all the people searching for easy questions - but at the same time it means, that SO is becoming a site for newbies as answer to hard/specific question has less points than answers to easy ones! I will do not do it anymore

  • There's no direct benefit to upvoting someone. You only get points from being upvoted or having the accepted answer. You'd need a fairly large cartel to make it worthwhile, as one person can only upvote something once.
    – Marc B
    Nov 9, 2011 at 19:45
  • 2
    @MarcB i'm afraid you did not understand my point... not the 'cartel' upvotes but any usual users, me and you. just because we see that answer is absolutely right. But, it's too easy to write right and popular answer to an easy question. that's the cheating. somebody creates 'situation', and probably the same person make this 'situation' useful for yourself
    – javagirl
    Nov 9, 2011 at 19:56
  • @javagirl: Yeah, sometimes I can hardly believe too, that there are so many fellow SO member who can give a better answer then me in less time :) And you may be right in some rare cases about the questions being staged. But I believe, most of the time it is just the way it goes.
    – bpgergo
    Nov 9, 2011 at 20:07
  • @javagirl: I hope you don't mind the (rather large) edits I've made. I tried to make your meaning clearer. I can scale it back if you want me to.
    – jscs
    Nov 9, 2011 at 20:12
  • @JoshCaswell as you wish. Thanks.
    – javagirl
    Nov 9, 2011 at 20:12
  • 3
    @javagirl - You can query the data dump yourself to see if you can spot these patterns. I just did and didn't see anything that struck me as suspicious. The answerers who respond to the same questioner multiple times tend to be those with a lot of answers generally. Nov 9, 2011 at 22:25
  • 2
    @javagirl if all you know is Java then you're right that question seems silly. But what if you worked in OpenEdge ABL or some other language without case fall-through for your entire career? In that light it's a perfectly valid question, and does indeed contribute to the community. The only reason it would be closed if it (and I anticipate it is) an exact duplicate of another question.
    – corsiKa
    Nov 10, 2011 at 19:49
  • I'd also like to point out that... you also answered that question, and it's currently the highest voted answer you've ever made. So exactly how unethical is it to answer again?
    – corsiKa
    Nov 10, 2011 at 19:52
  • @glowcoder exactly, I was wondered why I received so many upvotes (for me) for so trivial thing as it was
    – javagirl
    Nov 10, 2011 at 19:58
  • @glowcoder why he/she does not look into the specificaion if he write in the new language? if i will write programs on the perl/scala/whatever I'd better start RTFM than posting trivial things here
    – javagirl
    Nov 10, 2011 at 19:59
  • 1
    @javagirl because once you know the answer you know where to look and then it's easy. Before that, you don't necessarily know where to look.
    – corsiKa
    Nov 10, 2011 at 20:03
  • @javagirl: "Programmers seem to have stopped reading books." - an interesting story begins after that line.
    – Shog9
    Nov 10, 2011 at 20:13
  • @glowcoder its not right. I never asked such a questions before reading the basics - and the specification of a new langauge it's basic thing. or just confirm that SO is for newbies
    – javagirl
    Nov 10, 2011 at 20:14

5 Answers 5


So wait, lemme see if I've got the particulars of this dastardly scheme straight...

  1. Person A asks a reasonable question.
  2. Person B provides a good answer to it.
  3. Other folks up-vote the answer (and maybe the question).
  4. A&B make off with loads of meaningless rep, while the site is stuck with another good question and answer pair.

The bastards!

  • 4
    I'd say this is the correct answer by any meaningful analysis :) Nov 9, 2011 at 21:16
  • A person could make a fortune (in meaningless rep, of course) by simply asking integer division questions using sock puppets and answering with a canned response each time. How does this enhance the site? Only if the question gets deleted, a relatively rare event even for dupes, do the votes get removed.
    – tvanfosson
    Nov 9, 2011 at 21:22
  • Lol.. evil knows no bounds
    – JK.
    Nov 9, 2011 at 21:23
  • @tvanfosson: how is this any different from the folks that ask hundreds / thousands of basic, localized questions... the folks that spend all day answering basic, localized questions... and the folks that up-vote this Q&A? There doesn't need to be any external relationship between folks for this to happen, nor does such a relationship necessarily help much; the willingness of folks to up-vote useless crap lifts all boat-programmers.
    – Shog9
    Nov 9, 2011 at 21:26
  • 15
    xkcd.com/810 Nov 9, 2011 at 21:31
  • 3
    yep, but this pair was not good. it's unuseful, it's spamming and it's only a visibility of problem. btw, as rep is meaningless - give yours to me
    – javagirl
    Nov 9, 2011 at 21:42
  • 5
    I'm going to assume @MichaelMrozek's link is to the comic about spammers and upvote blindly.
    – mmyers
    Nov 9, 2011 at 21:42
  • 6
    @javagirl: if you see an unhelpful question or answer posted, downvote it. Regardless of who posted it. If it's too localized, or off-topic, flag or close as well. Regardless of who posted it.
    – Shog9
    Nov 9, 2011 at 21:46

I am not sure if there's an actual problem here. Even if this is done deliberately, if:

  • the question is not a duplicate, and
  • it's likely to help other users in the future, and
  • they are not upvoting each other

Why not? I don't know what's your beef with this whole thing is. If the overall quality of the site improves with the answer, what's the problem here?

I noticed that sometimes, when someone asks a stupid and easy-to-answer question, almostly instantly, a full, good answer from another user appears

You just have to be the FGITW. As long as you get the answer in, it can be edited within the first 5 minutes posting it. Once you get used to it, it's not surprising how much you can write in those 5 minutes.

If your problem is with the question being "stupid," this is a well known problem: The bikeshed problem and Stack Exchange. But this happens regardless of whether or not the asker and the answerer "colluded".

  • what's the FGITW?
    – javagirl
    Nov 9, 2011 at 21:08
  • @java: The "Fastest Gun in the West"
    – jscs
    Nov 9, 2011 at 21:12
  • right, this FGITW is the problem. if it will be solved (i personally prefer random order or hiding score) this 'cheatings' will be not so obvious
    – javagirl
    Nov 9, 2011 at 21:32
  • 3
    FGITW isn't a problem. It's sort of a feature...
    – Shog9
    Nov 9, 2011 at 21:49
  • @Shog9 it is, unless there would not so many people suggesting the different solutions
    – javagirl
    Nov 9, 2011 at 21:59
  • 1
    @javagirl, a quick glance around this site will quickly demonstrate the willingness of folks to propose "solutions" to just about anything that has ever even momentarily bothered them... Regardless of whether or not their personal annoyance is part of a larger problem. There's also a pervasive idea that the site would be infinitely better if down-voters would be forced to post comments... It's worth reading past the "solutions" to the bit where others critique them.
    – Shog9
    Nov 9, 2011 at 22:08
  • @Shog9 why are you talking this to me? jsut go to that question FGITWP and downvote all the useless 'folks' with their stupid 'solutions'
    – javagirl
    Nov 9, 2011 at 22:30
  • What makes you think I haven't, @javagirl? Read the top two answers under that question - they're both pretty clear on why we don't want to discourage fast answers.
    – Shog9
    Nov 9, 2011 at 22:37
  • @Shog9, i see, you are one of those who prefer doing things fast&superficially than thoughtfully&deeply
    – javagirl
    Nov 9, 2011 at 22:49
  • That's pretty accurate, @javagirl - but I also make quick, superficial judgements.
    – Shog9
    Nov 10, 2011 at 20:09
  • @Shog9 excellent characteristic for a person who pretend to be a moderator
    – javagirl
    Nov 11, 2011 at 12:33
  • Indeed, @javagirl - gotta be quick on your feet, so to speak!
    – Shog9
    Nov 11, 2011 at 22:11
  • @Shog9 yes please ban me
    – javagirl
    Nov 12, 2011 at 0:33

Yes. There is an algorithm that detects unusual voting patterns and negates votes cast by actual sychophants and sock puppets alike. This includes both up votes and serial down votes.

See the FAQ, How does the SO voter fraud detection mechanism work?

EDIT: I'm not sure if the voter fraud detection algorithm works to detect shill accounts or not, but it shouldn't be hard to add this if it doesn't. All you would need to look for is the percentage of votes achieved for a user's answers grouped by the question poster.

  • Read the question again. Someone has two accounts. They post a question with one. Then they post a good, prepared answer with another, before anyone could potentially write an equally good answer. They don't get any penalty for asking a bad question on the real account, and they unfairly get a competitive advantage in answering and the +15 accept bonus. No voting irregularities to be detected, as the asking account is a throwaway.
    – agf
    Nov 9, 2011 at 20:01
  • So. Assume next situation. My husband has account here, and so do I. We create the pair - question-answer. In the time when here are not so many users for example. He asks, I instantly answer. We surely do not doing any upvotes for each other. Why? because obviously there will be enough upvotes from other users when they will se that my answer exellently suits my husbands's question, and when this answer will be the most first
    – javagirl
    Nov 9, 2011 at 20:04
  • 3
    @agf - he did read the question. The scenario you described is the classic sock-puppet, which tvanfosson says SO has algorithms to detect. Nov 9, 2011 at 20:04
  • 1
    @Adam: The question isn't talking about two users upvoting each other. It has been edited to make this explicit.
    – jscs
    Nov 9, 2011 at 20:13
  • So i cannot see any possibility of detecting these situations I described. Could you please add any remarks about this algorithm for this particular case?
    – javagirl
    Nov 9, 2011 at 20:15
  • 1
    @Josh - yes, you're right, I see that now. Nov 9, 2011 at 20:15

I don't think this is particularly harmful in small doses. It wouldn't even be an issue if it were just one account (It's OK to answer your own question) I think it would be reasonable to extend this principle to this case with the following provisos:

  1. It's not all the activity from one or both of the users in question
  2. The questions genuinely are of interest, not duplicates for instance.

Imagine the scenario of two colleagues, let's call them A and B for simplicity:

A: Is it reasonable to frobnicate X with Y?

B: Good question I'm not sure, I'll check on Stack Overflow, someone's bound to know there
B: Wow! Nobody's asked that yet, let me look into it
B: Turns out it's explicitly mentioned as a bad thing to do in the X manual

A: Interesting, I'm surprised nobody has asked about this yet, we should share this Q&A with others

If A and B only participated in this kind of behaviour then I think it is definitely abusive, presumably the end goal would be gaining access to privileges and using them for nefarious deeds of one kind or another. In that case it's fairly easy to spot and only takes one flag (manual or automatic) to defeat.

As it stands though I think this is perfectly fine in exactly the same way self-answering is - reputation should reward correct and accurate answers which expand the body of (topical) knowledge encapsulated on the site. This scenario clearly adds to the total knowledge and is in no way intellectually or morally dishonest.

  • Another proviso, though less strict, might be that A wait a while to see what other useful answers come in (as is mechanically enforced for self-answers), rather than immediately awarding the checkmark to B.
    – jscs
    Nov 9, 2011 at 20:55
  • @JoshCaswell - I think that might be a useful etiquette heuristic for the cases where this isn't a one-off between the two users.
    – Flexo
    Nov 9, 2011 at 20:58

I'm borrowing from Shog9's answer, just to see if I understand javagirl's complaint.

So wait, lemme see if I've got the particulars of this dastardly scheme straight...

  1. Person A asks a duplicate, simple question.
  2. Person B provides a good answer to it, that has already been prepared.
  3. Other folks up-vote the answer (and maybe the question).
  4. A&B make off with loads of meaningless rep, while the site is stuck with another simple question and answer pair.

javagirl, do I understand what you're stating?

Over the course of a year and some months on Stack Overflow, I've seen plenty of easy to answer Java questions. In fact, Joda time is used so often as an answer, it's a meme on Stack Overflow.

I've seen people answer Java questions that I know have been asked before. Why? Because it's quick reputation.

Now, I don't know how many people are gaming the system as javagirl suggests. But I know that I've seen what I believe she's describing. Obviously, I don't know if the questioner and answerer are in cahoots.

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .