E869120's blog

A mystery of CF contribution distribution
By E869120, 8 years ago, In English

Recently, I'm interested in CF rating and contribution distribution, and I searched this.
I already searched about mysteries of rating distribution (Blog), so I wrote here about contribution distribution. (Thank you for comments)

Method of Searching

  • Here is the leaderboard of top contributor.
  • I searched the rank of contribution -51, -46, -41, -36,..., -1, 4, 9, 14,..., 164, 169, 174, 179. I searched the number of contributors too.
  • Then, I make the distribution graph.
  • Each range of the graph is [-inf, -50), [-50, -45), [-45, -40),... , [175, 180), [180, inf]. Each value of x-axis of the graph is the minimum value in range. For example, if the value of axis is 15, this means the range is [15, 20).
  • The minumum value of range [-inf, -50) is inf, but in distribution graph this value is -1000.

However, there was some surprising thing about it.
Look at following graph:

Note: The distribution graph has Logarithmic scale. Every time the scale increases by 1, the value doubles (2 times).

The surprising things are following:
  • Obviously, the number of people who have contribution [100, 105), [105, 110), [110, 115) is especially larger than [90, 95), [95, 100).
  • The number of people decreases greatly from contribution [10, 15) to [15, 20). The difference is approximately 2.5 times.
  • The number of people who have contribution [-50, -45) , [-45, -40), and [-40, -35) are nearly the same.


Why these things can be occur?

UPD1: rng_58's contribution became 180, so the graph was extended. Wonderful.
UPD2: The distribution graph is extended because some user's contribution was changed.

  • Vote: I like it
  • +43
  • Vote: I do not like it

Comments Comments (25)
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8 years ago, # |
  Vote: I like it +35 Vote: I do not like it

That thing around 100 threshold is particularly surprising. If analogous thing would happen for example about 2400 rating then we would be able to get away with sth like "people stop competing after they reach red", but it is hard to control contribution like that (people can still upvote/downvote your comments), stopping writing comments sounds weird and most importantly, contribution vanishes with time, because comments/blogs created multiple of 6 months ago lose their influence which makes contribution really a liquid thing.

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8 years ago, # |
  Vote: I like it +74 Vote: I do not like it

Request: search the correlation between rating and contribution.

It's obvious that red coders are getting more plus votes on their comments/posts, but I don't know how much it's correlated.

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    8 years ago, # ^ |
      Vote: I like it +43 Vote: I do not like it

    I think that there is something more behind it than simply "he's red, so probably it is clever, upvote" ;p. However seeing some stats about it would be indeed interesting

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      8 years ago, # ^ |
        Vote: I like it 0 Vote: I do not like it

      Actually, that's exactly what people do.

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        8 years ago, # ^ |
          Vote: I like it +31 Vote: I do not like it

        I definitely agree that there is a psychological tendency to perceive red's comments/blogs as better (more clever/mature/funny etc) than same ones posted by eg blue, but my point is that it is definitely not main factor because average red's comment is in fact of significantly higher quality than average blue's comment. By no means I claim that all blue's comments are not worth reading and that all red's comments are worth reading, but you can't deny that on average there is significant correlation between rating and quality of comments

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          8 years ago, # ^ |
            Vote: I like it -16 Vote: I do not like it

          I'm hesitant to agree or disagree with you. No doubt red people have a lot of knowledge related to technical things ... but what about the comments/threads which aren't about programming at all ? In those kinds of questions, I don't think red people have a higher quality of comments..

          But, red people have more knowledge and can help out better with programming/problem solving questions.

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            7 years ago, # ^ |
              Vote: I like it +29 Vote: I do not like it

            I tend to disagree with you, as problems solving skills is highly correlated with intelligence and wisdom, so I think it applies to things that are not related to programming too.

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    8 years ago, # ^ |
      Vote: I like it 0 Vote: I do not like it

    It is ... If I wrote the exact same comment, I would probably get a few downvotes for no reason ... lol.

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    7 years ago, # ^ |
      Vote: I like it +15 Vote: I do not like it

    Another reason can be that red coders simply do write more comments.

    If you'll take a look at active CF spammers or even at people who take part in a lot of discussions, number of reds among them will be really huge already. And when you take percentage of red coders who are actively involved in community life and compare it to the same value for green coders — difference will be very big.

    Yet I agree on "red get more upvotes" part as well.

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    7 years ago, # ^ |
      Vote: I like it +5 Vote: I do not like it

    Thank you for EnumerativeCombinatorics, and readers of the blog.
    I searched the correlation between rating and contribution in this blog:
    Link

    If you have some comments, impressions and questions to blog, please comment!

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8 years ago, # |
  Vote: I like it +28 Vote: I do not like it

Is the contribution formula known? Most recent data I could find is from 4 years ago and it doesn't state the exact formula, only that the function is monotonic. Maybe contribution 100 is some special point?

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    8 years ago, # ^ |
      Vote: I like it +18 Vote: I do not like it

    I think if the special point exists, it may be 101.
    Because the contribution and the number of people is following:

    Contribution 99 100 101 102 103 104 105 106
    Number of people 2 2 11 9 8 6 6 2

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8 years ago, # |
  Vote: I like it +40 Vote: I do not like it

~100 is approximate contribution one gains after setting CF Round, 'cause Round announces and editorials usually get many upvotes. Maybe that's the reason?

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    8 years ago, # ^ |
      Vote: I like it +29 Vote: I do not like it

    Exactly. Since the contribution grows slower on the top, holding a round will always bring the contribution value to a bit over 100, regardless of the writer's previous contribution (as long as it's < 30 or so).

    So to me seems like a notable coincidence. Though I have come across an exception in a championship (it was VK Cup 2017 - Round 3) way back.

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      8 years ago, # ^ |
        Vote: I like it +13 Vote: I do not like it

      I agree.
      But some announces and editorials of CF round gets many downvotes.
      For example:
      Codeforces #382 Editorial (-229 downvotes): Here

      So I don't think that all of the writers gain +100 contribution at least once, but I agree that most of writer gain +100 contribution at least once.

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      7 years ago, # ^ |
        Vote: I like it +25 Vote: I do not like it

      It was in russian, right?

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        7 years ago, # ^ |
          Vote: I like it 0 Vote: I do not like it

        No, it was written by tourist and got him a lot more than just 100 contribution.

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          7 years ago, # ^ |
            Vote: I like it +13 Vote: I do not like it

          Never mind, it's just another "coincidence" meme...

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            7 years ago, # ^ |
              Vote: I like it +5 Vote: I do not like it

            Ah, thanks. It didn't click in my mind at first.

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7 years ago, # |
← Rev. 2   Vote: I like it -13 Vote: I do not like it

There is an interesting increase starting from 90, there is probably a special case for reaching 100 in codeforces' algorithm. Pretty good work by the way.

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7 years ago, # |
  Vote: I like it +21 Vote: I do not like it

recently i wrote my first comment on someone's blog and my contribution became -1 and I was a little worried but after seeing this post i know some people have -100. so this means i am still in a very good position.

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5 years ago, # |
  Vote: I like it 0 Vote: I do not like it

Can someone explain jack_peralta's contibution? He has neither authored a blog nor written a comment.

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    5 years ago, # ^ |
      Vote: I like it +1 Vote: I do not like it

    Maybe, wrote blogs, got down voted, contribution stayed

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    5 years ago, # ^ |
      Vote: I like it 0 Vote: I do not like it

    He wrote some bullshit blog about MikeMirzayanov getting involved in an accident today.I can't find the heavily down-voted blog, so I guess it was deleted and hence the negative contribution.

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      5 years ago, # ^ |
        Vote: I like it 0 Vote: I do not like it

      I thought it was some bug..thanks!

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