# Unpinning the accepted answer from the top of the list of answers on CV

See the relevant thread at Meta.SE. As of Sep 8, answers on SO are sorted differently than before: previously, accepted answers were always shown first, but now, answers are strictly sorted by votes. SE are collecting feedback until Sep 19 as to whether other sites would like to also implement this.

Where the most upvoted and accepted answers differ, I agree that the most upvoted is usually better. So I'm for the change but don't feel very strongly about it. It seems likely to affect a relatively small proportion of answers (anyone know what % we're talking about?) and the difference in quality in these cases is often fairly obvious.

EDIT: Based on @Scortchi's SEDE query above, this change presently affects 2899 questions, or about 1.5% of all non-deleted questions the site has ever received.

• (+1) When there is a really big difference, the explanations seem to range from timing (the OP accepted an early answer and didn't change even though a much better answer came in later) to perversity (the OP accepted what they wanted to hear, despite being told that their question was misguided or that there is a much better idea). Again, quantifying those various reasons would be interesting but difficult. Optimists would emphasise timing, pessimists perversity. Sep 15 at 9:15
• @NickCox Indeed. Your comment reminded me of this entertaining example, which happens to hold the CV record for biggest score difference between most upvoted and accepted: stats.stackexchange.com/questions/20836/…
– mkt
Sep 21 at 12:44

I agree that this is a worthwhile change, but I think a slight augmentation would be ideal. Currently, you can sort answers several ways (by votes, by default, but also by recent activity or age). It would be helpful to have a sort option that returns the old style ordering (accepted on top). There can be cases with lots of answers and it might be helpful to see the accepted one quickly without having to scroll though everything.

This isn't a proposal for action but rather an extended comment that flags up some things we may want to keep an eye on if this change goes ahead. I suggest distinguishing static considerations, whereby orderings of historic posts already in our repository may change, from dynamic effects this change might produce on voting on new questions. Much of the discussion, and indeed cited data, concerns the former but the latter effect is less clearly evidenced. It's well known that answers listed at the top of a page tend to receive more votes, because not everyone scrolls down to read the lower ones. This is one of the problems with treating the voting system as if it were a rating system (as @SextusEmpiricus points out).

Sometimes an excellent answer is posted weeks or months after a question was first answered, and such answers inevitably struggle to catch up with ones posted when the question had its higher initial traffic. Occasionally these answers represent changes in the state of the art, e.g. when a new paper has been published (or particularly on StackOverflow, when there are a changes to a programming language or library, as anyone who regularly refers to the ggplot2 resources there will tell you while tearing any remaining hair out). Such answers often really deserve to be the top-listed, and a voting system will only rarely achieve this. There are ways to try to influence the votes, like high-rep users promoting the answer by posting a bounty for it and deliberately leaving it in the bounty queue to encourage more eyeballs/voters, but when a question was initially popular and the original answer garnered dozens or even hundreds of votes, it's very hard for a new answer to overcome that kind of lead even if it technically supersedes prior ones.

• "the green-ticked answer accumulates votes more rapidly to catch up or surpass the previously best-voted answer" This is a very interesting mechanism that should be easy to test. In this question on meta I assembled a bunch of graphs displaying how the voting system works. I will see if I can get some time to make insightful graphs about the 'battle between answers' and the effect of being on the top of the page. Sep 20 at 15:39
• My comment cited optimistic and pessimistic guesses at why voting doesn't match a perception of quality without saying how often I lean towards either. There is no evidence there for how charitable or uncharitable I am compared with anybody else. I'd say anyone who answers just one question on CV is thereby more charitable than the large tribe of those who lurk but don't even try, despite having appropriate expertise and experience. (Not offended or irritated at all ; I take your comments as typically good-natured.) Sep 21 at 9:29
• @NickCox Duly edited to better represent what I intended to convey! (I do think there's some truth in your inner pessimist's observation that some people are just waiting for an answer that agrees with their preconceptions, and mkt's example is one of the more famous cases. But often the perverse choices strike me as occurring when some minor, obscure or idiosyncratic point was the trigger that allowed the OP's penny to drop. I suppose I might restrict myself to saying that most of the time I feel more charitable about perverse green-tickers' intentions than Nick Cox's inner pessimist!) Sep 21 at 19:28
• "Answers even a few minutes earlier than another have a few more votes, get a higher position on the page, and as a result tend to attract even more votes, since not all readers/voters scroll down far enough to see the newer answers." Slightly off-topic, but I think this is a good argument for randomising answer order for perhaps 1 day or 1 week after the question is asked.
– mkt
Sep 22 at 8:19
• @mkt Indeed, is an answer that has been on the site for 10 hours and accrued 15 upvotes "really" better than one that has been on the site for 4 hours and accrued 12 upvotes? Rather than a purely random order, you might take the current vote totals and fuzz them a bit by adding some random noise, perhaps granting "younger" answers more standard deviation to their noise to reflect greater uncertainty about their ultimate vote count. Ultimately, we want answer order to reflect usefulness for future readers. But ordering interacts with vote count which interacts with ordering... Sep 22 at 12:32
• @mkt Answers are originally written for the benefit of the OP, who likely reads all answers & ordering matters little to them. The initial viewership wave largely is site users who saw the question on a feed (or sister site users via Hot Network Questions) who also form the main votership. Perhaps presenting a "correct" ordering to "browsing & just curious" viewers/voters is less important than getting ordering "right" for future readers who actually have that problem and arrive via search engine. If randomising during the main voting wave improves ordering, it may be a worthwhile tradeoff Sep 22 at 12:40

The 'accepted answer' is a way for the questioner to

• grant a specific answer a bonus
• notify that their problem/question has a sufficient answer (it provides a way to close the question; at least from the point of view of the questioner)

There seems no good reason to me why the questioner should be granted powers to influence the order of answers except for one potential problem...

• Some questions have a long history and because of this there develops a large discrepancy between votes. For instance, at Cross Validated, a 'hot network question' can gather a large amount of votes in just a day. For that situation, a late answer will never catch up with the votes but might be a better answer (it breaks the voting system, which in my opinion doesn't work correctly because it is not a rating system).

In such a case it is nice when the questioner can bump up an answer beyond discrepancies in votes. The accepted answer can be a better measure than the votes, or at least it is good to have it in addition to the votes.

So in principle I do not see why the 'accepted answer' should be on top. But in practice there is a good reason to have it on top. I guess that on CV it would be good to stick with the old way and choose for the practical reason to have it on top. There is not much harm in having the accepted answer on top. (One case would be when the accepted answer would be bad, but that problem should be dealt with differently.)