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    Explaining level changes

    Charlie Pomphrey v Jamal Alexander (Sat 07 Jan 2012)

    Match won by Jamal Alexander. Result: 9-11,11-9,1-11,11-6,4-11.

    Starting level for Charlie Pomphrey: 30, level confidence: 10%.
    Starting level for Jamal Alexander: 35, level confidence: 10%.
    Jamal Alexander to win as he is currently playing 17% better than Charlie Pomphrey.

    Jamal Alexander won 60% of the games and 57% of the points.
    This games result would be expected if he was better by around 10%.
    This points result would be expected if he was better by around 33% (PAR scoring).
    These are weighted and combined to calculate that Jamal Alexander played 16% better than Charlie Pomphrey in this match.

    Special case for levels < 100 as these are often players who are new to the game and getting better fast. Levels can change quickly for these players and a default level increase of 1 has been added to both players for playing another match.

    Without any limiting, both players would need to be adjusted by 0%. The level change for Jamal Alexander has not been limited and has increased to 36. The level change for Charlie Pomphrey has not been limited and has increased to 31.

    Increase level confidence due to one more match played. Jamal Alexander: 22%, Charlie Pomphrey: 22%.
    Reduce level confidence based on how much adjustment is needed. Jamal Alexander: 22%, Charlie Pomphrey: 22%.

    A final adjustment of +568.8% has been made to both players as part of the automatic calibration that is performed after each match. All players in this pool will have been adjusted equally in order to remain equivalent to other player pools.

    Final level for Charlie Pomphrey: 208, level confidence: 22%.
    Final level for Jamal Alexander: 240, level confidence: 22%.

    Notes

    • This calculation is done in two main parts; first work out the adjustment needed to match the results and then apply damping. This means that levels should always be 'about right' but the time taken to get there or the volatility is dependent on the damping.
    • A level also has 'level confidence' which drops if players haven't played for a long time or have had enexpected results. As low confidence levels adjust more quickly than high confidence levels, it allows these players to find their level more quickly without impacting their opponent's level too much.
    • Point scores are used as well as game scores for accuracy - particularly important for 3-0 results - though we can work with game scores only too, albeit with more damping.
    • Mismatched players are allowed for - you don't have to hammer your opponent. See explanation above if this applies to this match.
    • The section on damping is where we still have some options. We have recently made a change to damp league matches more than tournament matches and box matches even more than that. This gives added weight to the more important matches.
    • There are occasional, very small adjustments made to all players to keep the averages constant which are not covered here.
    • You don't get a bonus just for winning - if you want to go up you have to play better than expected against your opponent.
    • We have spent more than 5 years fine tuning the level calculations based on tens of thousands of match results and a great deal of feedback from players, team captains and coaches. It's the most usable and accurate ranking system there is in any sport, let alone squash.
    • For a more complete explanation of how levels are calculated (on which this system is based) see the help file here.
    • If you have thoughts/opinions on the above or any feedback on the way levels are calculated or updated, please contact us. We welcome all feedback, although we are keen squash players ourselves and would pefer to be on-court than in front of a screen so please be patient and please do try to see if your question has already been answered on the help page. We are unable to answer questions about hard anyone played in their match - we only get to see the results - and if your level didn't increase as expected please make sure you've looked at the above explanation before contacting us. If you want to go up the levels, train harder, listen to your coach and win more points. Or just be incredibly talented!