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the world of the ELO rating system Mariia Koroliuk Nicholas R Moloney
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Feb 15, 2021

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  • the world of the ELO rating system

    Mariia 
Koroliuk

    Nicholas

    R Moloney

  • ELO rating in the real life

    screenshot from the movie “The Social Network”

  • A -rating Ra B -rating Rb

    - expected score (for A)

    S - gained score (for A)a

    - new rating for A

    vs.

    …and in the chess

  • experience

    K = 40 (30 before july 2014,25…)

    30 games 18th birthday

    2300

    K = 20 K = 10

    2400

    K factor (FIDE official since July 2014)

    (whatever happens first)

  • issues

    • Game activity versus protecting one's rating

    • Selective pairing

    • Ratings inflation and deflation. Example, Around 1979 there was only one active player (Anatoly Karpov) with rating >2700, September 2012 - guess? 44

  • DataData comes from https://ratings.fide.com that

    publish the records every 3 months since 2001 and every months since September 2012.

    https://ratings.fide.com

  • Distribution of different ratings

  • Data

  • Typical evolution over time

    time (1=3 months period since Jan 2001)

    ELO

    ratin

    g

    selected players , that plays actively and around 30 years old at t=0

    AR(1)?

  • Linear around (0,1/2) with m=0.0014

    theoretical prediction:
coefficient: 1-mlk=0.78 for L=10 (games) K=15
(average parameters)

    We proved, that the score evolution for stable active player is an AR(1) process both empirically and theoretically with parameter alpha of 1-mKL (m- scope of the curve, L -average amount of games per time interval) and variance that depends on how much player vary in good days and bad days.

  • Estimation Results 1 -variance

    stronger players plays more stable

  • Estimation Results 2 -alpha

    predicted level

    only regular players born from 1970 to 1975

    ?

  • WHO IS THIS GUY?

    Palac,

    Mladen

    time

    ELO

    ratin

    g

    played a lot!

    around 50 games

    Recalculate alpha:

    coefficient: 1-mlk=0.4 for L=50 (games) K=10

  • diffe

    renc

    e fro

    m th

    e m

    ax

    learn

    ing p

    eriod sta

    ble period (AR(1))

    decline

  • Learning periodWe also proved, that if person enters the list with some fixed stable level starting from smaller level learning much evolve in exponential speed.

    However, predicted speed of learning is always higher that empirical speed. 


    The explanation is that 
We are improving while learning.

  • extreme values

    Is there some possible maximum?

    What are the chances for a really-really strong player (more

    that 3000) being born in next year?

    Generalized Pareto Model: really good fit- helps to explore events, that never

    happened

  • data stops here,

    but the model could be

    continued

    What is the chances

    the event of person

    with 3000 ELO will appear?

    p=4e-10


    exampleconditional probability on p>2600

    1-(1-p)^n=0.1 —> nlog(1-p)=log(0.9)

    —> n=2E8 


    now there is p=7e4 players in FiDE list.

    on whole earth,

    there is 7E9 people
(which means

    that
1 out of 100000

    plays chess professionally)

    so there need to be 1E10 professional players ->
1E12 people

  • SADLY, there was only 1E11 people ever on the earth

    NOt to add on a sad point, as was said:

    “A theory has only the alternative of being

    right or wrong. A model has a third

    possibility: it may be right, but irrelevant.”

    and not every prediction is a true one.

  • THank you and time for questions