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    Explaining level changes

    David Aimson v Graham Woodage (Fri 20 Dec 2019)

    Match won by Graham Woodage. Result: 8-11, 10-12, 9-11.

    Starting level for David Aimson: 260, level confidence: 41%.
    Starting level for Graham Woodage: 384, level confidence: 19%.
    Expected winner: Graham Woodage as he is 48% better than David Aimson.

    Graham Woodage won all of the games and 56% of the points.
    This games result would be expected if he was better by around 55% or more.
    This points result would be expected if he was better by around 27% (PAR scoring).
    These are weighted and combined to calculate that Graham Woodage played 36% better than David Aimson in this match.

    In this case, Graham Woodage played at level 361 and remained within his allowed range so his level will not be adjusted. On the assumption that Graham Woodage would normally have been playing at level 367 (based on typical behaviour), David Aimson played better than expected and therefore gains a pre-damping level increase of 1.7%.

    Due to the difference in level between the players, the adjustments have been reduced to 0% and 1.4% respectively.

    Factoring in the relative levels of confidence which allows players with low confidence in their levels to change more quickly, the adjustment for Graham Woodage changes to 0% and David Aimson changes to +0.6%.

    After applying standard match damping, the adjustment for Graham Woodage becomes 0% and for David Aimson becomes +0.6%.

    Apply match/event weighting which for 'Club match' is 50% leaving the adjustment for Graham Woodage as 0% and for David Aimson as +0.3%.

    Apply limits to the amount of change for a single match so that In general a player's level won't go up by more than 10% or drop more than 5% if they've played in the last 7 days but those limits are relaxed if their previous match was further back.

    Increase level confidence due to one more match played. Graham Woodage: 43%, David Aimson: 64%. Reduce level confidence based on how unexpected the result is. Graham Woodage: 41%, David Aimson: 61%.

    Final level for David Aimson: 261, level confidence: 61%.
    Final level for Graham Woodage: 384, level confidence: 41%.

    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!