nagitaosu's blog

By nagitaosu, history, 3 years ago, In English

Since I couldn't find the latest rating distribution of Codeforces, I created it.
This plot only includes active users who has participated contests more than 5 times.

Past rating distribution

UPD: The plot is updated (2020/04/01)
UPD: Thanks to Gosunov, this plot has been updated again! (2021/07/09)

 
 
 
 
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3 years ago, # |
Rev. 2   Vote: I like it 0 Vote: I do not like it

So according to the graph, there're more experts than specialists ? Interesting!

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    3 years ago, # ^ |
      Vote: I like it +32 Vote: I do not like it

    Expert is a 300 point band, whereas specialist is a 200 point band, so it's not that interesting :)

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

      What is interesting, though — is the odd jump at start of each band. I wonder why that happens

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        3 years ago, # ^ |
          Vote: I like it +75 Vote: I do not like it

        some people are reluctant to join contests if they think their rank will fall / they'll lose colour. So they sit at the lowest rating with their colour for a long time.

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          3 years ago, # ^ |
            Vote: I like it +11 Vote: I do not like it

          It would be even more distorted if you count inactive users

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2 years ago, # |
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Interesting. There are so many grandmasters. So I still got a long way to go

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2 years ago, # |
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Almost Binomial Distribution.Interesting!

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    2 years ago, # ^ |
    Rev. 2   Vote: I like it 0 Vote: I do not like it

    Actually It's not that interesting, binomial distribution is expected to happen in most distributions related to ratings.

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

What is the median rating?

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    2 years ago, # ^ |
    Rev. 2   Vote: I like it +2 Vote: I do not like it

    Here are the statistical features.

    count    77654.000000
    mean      1405.483233
    std        282.043970
    min        -43.000000
    25%       1247.000000
    50%       1371.000000 # median
    75%       1509.000000
    max       3681.000000
    
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      2 years ago, # ^ |
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      I think your data is fake. Rating 1509 can be in the top 25%? I can't believe it!

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        2 years ago, # ^ |
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        It may be correct, don't forget that in your first contest you rate starts from 1500 + There are people who make fake accounts and join like 1-2 contests and the leave it at like 1450-1600 rate

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

        It is the features for all active users. If you pick up who has been participated contests more than 5 times, it will be look like this.

        count    42762.000000
        mean      1436.048407
        std        356.742685
        min        -43.000000
        25%       1181.000000
        50%       1393.000000 # median
        75%       1645.000000
        max       3681.000000
        
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2 years ago, # |
  Vote: I like it +5 Vote: I do not like it

Interestingly, the first bar of any color is always taller than the last bar of previous color. It points to the fact that many people stop participating in rated contests once they achieve a particular color, isn't it? Facts from stats!

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

How did you create the rating distribution? Can you please share the code.

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2 years ago, # |
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Ah, the beautiful Central Limit Theorem at work.

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13 months ago, # |
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I have updated the plot. It has some significant changes

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    13 months ago, # ^ |
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    This shows quantity has increased a lot, quality is still in queue.

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      13 months ago, # ^ |
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      I think that this is largely the effect of https://codeforces.com/blog/entry/77890

      In the past, beginners started with a high initial rating. Then participating in contests naturally resulted in their rating going down into the grey zone. So people were motivated to abandon their old grey accounts and start new ones (with a high initial rating again). With this kind of behaviour, many people with actual low skills were not registered in the chart. Because of having too few contests. Or because of having their rating score somewhat higher than they deserve (thanks to multiple account re-rolling attempts and a bit of luck).

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    13 months ago, # ^ |
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    I have updated the plot. It has some significant changes

    Could you please redo it with the number of participations >= 6? Beginners with only 5 contests don't have their rating fully converged and are missing the last 50 points: https://codeforces.com/blog/entry/77890

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      13 months ago, # ^ |
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      Here it is. Plot with the number of participations >= 6. Slight difference

      Plot
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        13 months ago, # ^ |
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        Can I put this plot to the top, if you don't mind?

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    13 months ago, # ^ |
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    no. of contestants at the first bar of the next level is greater than last bar of the current level

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13 months ago, # |
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Similarity with the Boltzmann distribution law.

  1. Where speed = performance
  2. molecules = contestants

Data fit with the law