I have heard about vote fraud.

What is it?

By which criteria is a vote declared as fraud?

How we can find out about these sorts of activity?

What are the consequences of it?


What if I am visiting a user's profile and listing his questions and answers and I decide to upvote many of his answers because I find them useful? Will this also be considered as abnormal?

  • 1
    to clarify: your voting Jon this morning isn't what I would call "vote fraud"; it may, however, have accidentally hit the built-in detections as a false positive. So rest assured that nobody is accusing you of anything. Unless you are actually Jon in a disguise (which I seriously doubt), in which case it would be fraud. Jul 9, 2009 at 12:14
  • I don't think Jon needs to be in a disguise for rep grab.
    – phoenix
    Jul 9, 2009 at 12:19
  • Can I ask you one more question after all these discussion? How often can I vote for a posting?
    – phoenix
    Jul 9, 2009 at 12:20
  • You can only vote once on any single post. Jul 9, 2009 at 12:44
  • Actually what I intended was how often can I vote for a person's postings.
    – phoenix
    Jul 9, 2009 at 12:57
  • I think part of the difference in what you're describing would be if you went to a user's profile page, looked at their questions/answers and upvoted ONLY their posts, without reading any of the others to see if they were also helpful or more accurate. I.e. upvoting that user's posts just because they were the author. Jul 9, 2009 at 13:46

3 Answers 3


The exact criteria should remain private for obvious reasons, as should the methods of discovery. But a typical scenario is having two accounts and up-voting yourself from the other.

Possible consequences:

  • cancellation of votes
  • deletion of one or more accounts
  • possible suspension of the remaining account

See also:

  • What if I am visiting a user's profile and listing his questions and answers and I decide to up vote many of his answers because I find them useful?
    – phoenix
    Jul 9, 2009 at 11:48
  • That gets into an edge case that is (IIRC) discussed in the blog comments; and indeed people have been accidentally penalized by this in the past (by over-enthusiastic "fan" voting causing some votes to be revoked). I can't speak for the automated processes, but when manually reviewing unusual voting it is usually fairly easy to spot the difference. Jul 9, 2009 at 11:54
  • But how could a user be prevented from up voting answers that he considers deserve up vote.[whether its bulk or not]
    – phoenix
    Jul 9, 2009 at 11:58
  • Just vote as you see fit; let the system do the rest. I can't say more for... reasons. Jul 9, 2009 at 12:04
  • If you want to make sure all votes will be accounted for, review a few questions each day early (on UK time).
    – Vinko Vrsalovic StaffMod
    Jul 9, 2009 at 13:40

Example of vote fraud: this morning, I received 15 votes on Meta within about half an hour. Each was for a different answer. I mailed team@stackoverflow.com who checked and found out that yes, it was one person voting for everything with my name on it.

Those votes were then cancelled.

This is basically the scenario you describe in your question. I don't know the exact algorithm used, but such behaviour would be deemed suspicious at least, when manually checked.

  • 1
    Extremely sorry @Jon. That was me. But I up voted for the answers or questions that I found useful. But was not aware of this.
    – phoenix
    Jul 9, 2009 at 12:09
  • 1
    I was visiting your profile and was going through the posts. I found some useful and up voted them only.
    – phoenix
    Jul 9, 2009 at 12:11
  • Thanks Jon; I didn't want to volunteer this morning's case (although I knew about it), so I'm glad you raised it. Jul 9, 2009 at 12:11
  • Is it really "fraud" if you don't know about it? In most legal definitions of naughty acts, there has to be some deliberate intention on the part of fraudster.
    – Joe Schmoe
    Jul 9, 2009 at 12:12
  • @Joe Schmoe - I don't consider that any "fraud" as such happened; merely that detections were triggered (in this case, instigated by Jon himself). The same as when my bank phones me up because I've bought a new laptop and booked a holiday. Jul 9, 2009 at 12:18
  • Okay, in that case, why were the votes cancelled? As far as I can make out, they were intended as genuine votes because of a number of helpful answers. It's nice of Jon to seek not to accept them but I'm not sure that anything wrong happened here.
    – Joe Schmoe
    Jul 9, 2009 at 14:02
  • 3
    @Joe: I think the point is that by looking at all the answers that one particular user has made and voting up all the useful ones, that gives a distinct bias to that user, as opposed to looking at a random cross-section of answers. It's not that the answers necessarily aren't helpful, but it's not giving sufficient consideration to other answers.
    – Jon Skeet
    Jul 9, 2009 at 14:12

It's kind of hard to say exactly what vote fraud is other than "votes that were gained undeservedly" such as when someone will go and vote everything from a user up or down regardless of the content of the question or answer.

The system already has an algorithm in place that does a pretty good job detecting irregular voting patterns. When something of the sort has been detected, it will inform the appropriate entity, and a rep recalc will likely be triggered on the voter and the recipients to make sure things are leveled out to the most accurate terms.

Consequences for repeated infractions can include penalty boxing and banning, I would assume.

  • What if I am visiting a user's profile and listing his questions and answers and I decide to up vote many of his answers because I find them useful?
    – phoenix
    Jul 9, 2009 at 11:49
  • 1
    Then don't do it in rapid succession that would look suspect.
    – TheTXI
    Jul 9, 2009 at 12:12

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