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https://www.youtube.com/watch?v=BGWVASxyow8&list=PLFAYD0dt5xCzTQHDhMPZwBoaAXWeVhZzg&index=19

The increase in popularity in sites is a completely seperate issue (albeit still pertinent). Although, if the average number of upvotes is increasing as the site grows more popular, it would induce a positive correlation between post number and score (the opposite of what I find). I would have to think about how to take that into account some more (perhaps a variable indicating the average score per answer site-wide for some time period before/during that post) but as is it wouldn’t be a valid explanation for why we don’t observe any reputation effects.

]]> http://stats.blogoverflow.com/2011/08/does-jon-skeet-have-mental-powers-that-make-us-upvote-his-answers-the-effect-of-reputation-on-upvotes/#comment-19 Fri, 05 Aug 2011 14:19:16 +0000 http://stats.blogoverflow.com/?p=143#comment-19 It doesn’t seem like the post number charts take into account the fact that older posts will have been around longer, and thus have more of a chance to be voted up or down. I certainly see a very long tail on the voting for answers I’ve given over the last couple of years.

This has come up a few times on Meta, where people have tried to state that questions and answers overall were receiving fewer upvotes nowadays, but they didn’t take into account the time people have had to find and vote for those older posts. No easy way to look at voting over, say, the first month a post had been live had been found from looking at the data dump.

Of course, if you were to localize the voting to just the first month a post had been live, you’d have to account for the increase in popularity of the site over the years, which might have an effect on voting patterns at the times the posts had been made.

]]> http://stats.blogoverflow.com/2011/08/does-jon-skeet-have-mental-powers-that-make-us-upvote-his-answers-the-effect-of-reputation-on-upvotes/#comment-15 Fri, 05 Aug 2011 12:07:10 +0000 http://stats.blogoverflow.com/?p=143#comment-15 @sbi , Sure that seems reasonable, and that is exactly one of the reasons I looked at score - (mean_score). You could have certain individuals that always have high numbers of upvotes due to certain tag participation, and (assuming) those are the individuals with the highest reputation, it would create a spurious correlation between reputation and score. When taking the difference from the mean score for all the answers within a person (assuming their tag participation stayed constant throughout their posting history), it essentially controls for that.

I have found this paper (Allison 1990) as a useful reference to illustrate this point.

]]> http://stats.blogoverflow.com/2011/08/does-jon-skeet-have-mental-powers-that-make-us-upvote-his-answers-the-effect-of-reputation-on-upvotes/#comment-12 Fri, 05 Aug 2011 08:24:27 +0000 http://stats.blogoverflow.com/?p=143#comment-12 Very nice analysis.

There’s one thing I disagree with, though: IME there’s a rather strong correlation between tag and upvotes. Whether you’re in an obscure tag where about 200 users even look at questions or in the realms of c#, java, android, and iphone does make a huge difference to your upvotes.