I’ve recently been involved in a few discussions around voting on Stack Overflow, and I think my own "policy" around it may be different to that of others. I thought it would be worth sharing why I personally vote items up or down, and hear your thoughts too. This blog may not be the ideal venue for such a post, but until such time as we have a real "meta" site for Stack Overflow (such as Stack Overflow Overflow) I can’t think of anywhere better to write about it. Readers who are only interested in coding should move on; I promise not to include anything about code in the rest of this post.

I’m going to assume that anyone who’s read this far is at least somewhat familiar with the logistics of Stack Overflow – in particular, how one votes and the effects on reputation. I’ll use the word "post" here to mean either a question or an answer.

I’d like to stress that this is in no way meant to be seen as an "official" voting guide – just how I happen to think.

Why vote?

There are two "audiences" for a vote in my view: the author of the post and the community who is reading the post and looking at the vote tally. The author can tell what votes they’ve received using the reputation tab of their "recent activity" page, whereas the readers can only tell what the overall tally is. Obviously the author also receives or loses reputation, too. This means the effect on the author and the audience are slightly different.

For the author, the immediate reward or punishment aspect may sound like the most important aspect: but I’d argue that for many users (particularly those with high reputation) the reputation for a single vote isn’t as important as the effect on the vote tally and what it communicates about your post. There’s usually a positive feedback effect on Stack Overflow: if one answer has a couple of votes and another has none, then the higher voted one is likely to get read more and thus garner more votes. The opposite can happen: an answer with a negative score will sometimes receive "sympathy" votes from users who think, "This answer isn’t brilliant, but it’s not bad enough to deserve downvotes."

For me, the important point about a downvote is that it may indicate I’ve got something wrong in an answer. I may have missed the point of the question in the first place, or simply provided a technically incorrect or unhelpful answer. I want to know about that, so I can fix my answer or delete it if I can’t actually provide any more useful information than is contained in other answers.

For the reader, the information communicated by the score can be as simple as "this question is interesting/this answer is helpful" vs "this is a poor question/this answer is harmful". I would hope that non-regular visitors will quickly get the idea that the highest voted answers are likely to be the best ones, and that answers with a negative score really shouldn’t be trusted. It doesn’t always work that way, but it’s a reasonable rule of thumb.

So, how do I vote?

How I react to questions

I generally upvote a question if it’s been well written and I think the problem is sufficiently common that it’s going to help someone else searching for it. I’ll also upvote it if it’s particularly interesting, even if it’s not a very general problem. I suspect I should upvote questions more often – and I also suspect that’s true of many users.

I very rarely downvote a question, however. If the question is inappropriate, I’ll usually vote to close it. If it’s badly written but intelligible, I’ll edit it. If it isn’t precise enough (just lacks information) I’ll ask for more information in a comment. I don’t see much use in downvoting. Now there are various users who don’t support the idea of closing a question at all, of course – and if closing weren’t an option then I would downvote instead. However, I personally support question closing (when appropriate, of course – I’m not saying every closed question deserved it).

How I react to answers

I will generally upvote an answer if I feel it’s correct and helpful. If there are multiple posts which effectively answer a question, I will usually upvote the best one, but others which provide other bits of relevant information may get a vote too. Again, I probably don’t upvote as often as I should.

I downvote if I see an answer as actively unhelpful: this is usually if it’s technically inaccurate, or suggests something which I think is a really bad idea (such as string concatenation in a loop without a small, known limit). I don’t downvote an answer just for being "not as helpful as it could be" or "not as helpful as another answer". I believe that behaviour discourages people from contributing in the first place, and an extra answer has relatively little cost associated with it. If it contains no information which isn’t present in another answer then I’d prefer it to be deleted, but I’d leave that suggestion as a comment rather than a downvote.

Speaking of comments, I practically always leave a comment when I downvote. A downvote means I believe something is really wrong with the answer, and it should be fixed: leaving it as it is makes the world a worse place than if it didn’t exist. A downvote without a comment is fairly pointless – it doesn’t help the poster to fix the answer, because they don’t know what they did wrong in the first place. I find it intensely frustrating when someone downvotes one of my answers without giving any reason: apart from anything else, that downvote could be made on the basis of a mistaken belief, but without that belief being expressed I have no way of correcting it. I always take another look at an answer which has been downvoted, but I’m much more likely to edit it if I’m given a specific reason.

Note that the reputation loss due to a downvote is almost insignificant – particularly if it’s early in the day (i.e. before very active users hit the 200 cap) – the idea that I’ve written something unhelpful is far more disconcerting to me than the loss of a tiny amount of rep.

I can see why users aren’t prompted for a comment on a downvote – it would be very easy to just type garbage, and that would be worse than no comment at all. It would also require the comment to be anonymised in order to keep the vote itself anonymous. Even so, I’d ask courteous readers to add a comment when you downvote one of my answers: I promise not to "retaliate" with a spate of downvotes, but I’d really like to be able to fix the answer!

In terms of editing, I will often edit an answer for formatting reasons or to correct a small typo, but I edit answers (from other people) less often than I edit questions.

How about you?

Enough about me – how do you vote? If you downvote without comments, what effect are you trying to achieve? When would you downvote a question rather than editing it, voting to close or leaving a comment? How do you react to downvotes to your own posts?