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Codeforces Round #480 (Div. 2) — thoughts about rating
By WasylF, history, 6 years ago, translation, In English

Hi there! Rules of div 2 only contests were updated recently (allowing to participate purple in div 2 only rounds). I'm curious does this have an influence on the rating system. So. I've split all participants of this round by divisions and calculated rating change for them independently. You could find this results via following links: div1 only, div2 only. .

Let's define average rating change in the division as a sum of all rating changes of each contestant from this division divided by the number of participants in this division.

Division Average rating change
div. 1 only -8.09
div. 2 only -10.68

Let's calculate average rating change for the official result (rating calculates without separating by divisions)

Division Average rating change
div. 1 +3.86
div. 2 -12.21
both -10.81

As we can see, in combined round average purple contestants gain almost 12 additional rating points. In my opinion, this is quite unfair. Your thoughts?

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

Comments Comments (6)
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6 years ago, # |
  Vote: I like it 0 Vote: I do not like it

Auto comment: topic has been translated by WasylF (original revision, translated revision, compare)

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

can we get same stats for div3 ?

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

    sure, average delta in previous div. 3 contest was -10.61. It's close to usual div. 2 round

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6 years ago, # |
  Vote: I like it +10 Vote: I do not like it

"As we can see, in combined round average purple contestants gain almost 12 additional rating points."

Can you explain this a little more? I'm not sure how this results from the table...

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    6 years ago, # ^ |
    ← Rev. 2   Vote: I like it +29 Vote: I do not like it

    3.86 - ( - 8.09) = 11.95

    So on an average the purple contestant benefits by around 12 points in div 1 + div 2 contests as opposed to div 1 only

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