some dull CF statistics: vanishing rating points

Revision en1, by Noureldin, 2020-05-20 03:39:41

things to do in quarantine

  • train to be better at CP
  • get some work done
  • generate some CF statistics

vanishing rating points

so I ran a python script that collected all rating changes of every rated round and I found some interesting stuff which can be found at the end of blog, however the thing that caught my attention is that rating points are vanishing at a rate of ~5.483 points/round/contestant!!!

the average rating change is negative ~ -5.483 points/contestant/round which is weired, you would expect that number to be around zero since the rating system scales everything so that the sum of ratings of contestants after each round remains the same as it was before the round, maybe a side effect of rounding ?

to verify this I compared the sum of rating of all rated accounts against what it should be, there are 258434 accounts that competed in at least one rated round, the sum of current rating of those accounts is 364795845 which is 22855155 (5.895%) less than what it should be 1500*(number of accounts) = 387651000

so why no one notices and ratings generally increase, it's -I think- because of the large influx of new accounts, each new account adds 1500 points to the pool of points once it starts participating in rated rounds so no one will notice ~5.483 points lost per contestant per round

if you think of the points as money and rating changes as transactions then you most likely won't notice that 5$ vanishes with each transaction from your account if each transaction involve $1000s, so basically we are acquiring points/money a lot faster than we are losing them and we won't start to feel the loss until the number of active accounts saturates, unless I'm missing something?!

so in a hypothetical scenario in which no new accounts are created and we just keep competing against each other and assuming all accounts are active we will all have ~ zero rating after ~257.44 rounds :V (or 6653.22 rounds if the number of contestants in each round is the -currently- more typical number of contestants of 10K)

how long you will need to reach high rating

you -probably- need -if ever- around 2.36 the time you needed to become a master to become LGM

the average number of rounds that contestants needed to hit a rank for the first time is summarized in this table

rank average number of rounds to become
Master 27.163
International Master 34.818
Grandmaster 39.651
International Grandmaster 47.638
Legandary Grandmaster 64.038
rank/percentile 0th25th50th75th100th
Master2.0 8.0 18.0 38.0 250.0
International Master3.0 12.0 25.0 48.0 213.0
Grandmaster3.0 15.0 30.0 55.0 274.0
International Grandmaster5.0 21.0 39.0 66.25 198.0
Legendary Grandmaster8.0 31.25 54.0 88.75 221.0
I wanted to list the accounts that reached each rank in minimum number of rounds however I found that most of them are fake accounts :\ :(

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en1 English Noureldin 2020-05-20 03:39:41 3665 Initial revision (published)