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Login: | Explaining level changesBen Wright v Helen Fay (Wed 15 Sep 2021)Match won by Ben Wright. Result: 15-10,15-12,9-15,15-8.Starting level for Ben Wright: 238, level confidence: 71%. Set manually. Starting level for Helen Fay: 350, level confidence: 48%. Helen Fay to win as she is currently playing 47% better than Ben Wright. Ben Wright won 75% of the games and 55% of the points. This games result would be expected if he was better by around 25%. This points result would be expected if he was better by around 20% (PAR scoring). These are weighted and combined to calculate that Ben Wright played 23% better than Helen Fay in this match. An upset! Assuming that any level changes are shared between both players, for this result it looks like Ben Wright actually played at a level of 321 and Helen Fay at a level of 260. 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 Ben Wright changes to +19% and Helen Fay changes to -28%. After applying standard match damping, the adjustment for Ben Wright becomes +10.6% and for Helen Fay becomes -15%. Apply match/event weighting of 50% for 'Workout Harbourside Boxes' so the adjustment for Ben Wright is +5.3% and for Helen Fay 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 Helen Fay 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. Ben Wright: 84%, Helen Fay: 69%. Reduce level confidence based on how unexpected the result is. Ben Wright: 63%, Helen Fay: 52%. A final adjustment of +0.5% 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 Ben Wright: 250, level confidence: 63%. Final level for Helen Fay: 338, level confidence: 52%. Notes
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