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Login: | Explaining level changesMartin Evans v Gary Sposito (Sun 28 May 2017)Match won by Gary Sposito. Result: 3-9,1-9,0-9.Starting level for Martin Evans: 227, level confidence: 63%. Starting level for Gary Sposito: 331, level confidence: 71%. Set manually. Gary Sposito to win as he is currently playing 46% better than Martin Evans. Gary Sposito won all of the games and 87% 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 164% (english scoring). These are weighted and combined to calculate that Gary Sposito played 164% better than Martin Evans in this match. Assuming that any level changes are shared between both players, for this result it looks like Gary Sposito actually played at a level of 445 and Martin Evans at a level of 169. Without any damping, both players would need to be adjusted by 35% to match this result. Allowing for the difference in level between the players, the adjustments have been reduced to 28% and 28% respectively. Factoring in the relative levels of confidence which allows players with low confidence in their levels to change more quickly, the adjustment for Gary Sposito changes to +25% and Martin Evans changes to -28%. After applying standard match damping, the adjustment for Gary Sposito becomes +13.3% and for Martin Evans becomes -15%. Apply match/event weighting of 50% for 'Westbury David Lloyd Boxes' so the adjustment for Gary Sposito is +6.6% and for Martin Evans is -6.9%. Apply limits to the amount of change for a single match which are based on player level, level confidence and time since last match so that Martin Evans is limited to -5% level change. 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. Gary Sposito: 84%, Martin Evans: 79%. Reduce level confidence based on how unexpected the result is. Gary Sposito: 63%, Martin Evans: 59%. A final adjustment of +1.2% 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 Martin Evans: 220, level confidence: 59%. Final level for Gary Sposito: 355, level confidence: 63%. Notes
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