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Login: | Explaining level changesAlice Clark v Richard Acklam (Sat 19 Aug 2023)Match won by Richard Acklam. Result: 2-15,5-15,2-15.Starting level for Alice Clark: 1,344, level confidence: 79%. Set manually. Starting level for Richard Acklam: 1,834, level confidence: 85%. Set manually. Richard Acklam to win as he is currently playing 36% better than Alice Clark. Richard Acklam won all of the games and 83% 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 400% (PAR scoring). These are weighted and combined to calculate that Richard Acklam played 400% better than Alice Clark in this match. Assuming that any level changes are shared between both players, for this result it looks like Richard Acklam actually played at a level of 3,511 and Alice Clark at a level of 702. Without any damping, both players would need to be adjusted by 91% to match this result. Allowing for the difference in level between the players, the adjustments have been reduced to 73% and 74% respectively. Factoring in the relative levels of confidence which allows players with low confidence in their levels to change more quickly, the adjustment for Richard Acklam changes to +68% and Alice Clark changes to -74%. After applying standard match damping, the adjustment for Richard Acklam becomes +24.1% and for Alice Clark becomes -30%. Apply match/event weighting of 50% for 'Redland Green Boxes' so the adjustment for Richard Acklam is +12% and for Alice Clark is -13%. 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 Richard Acklam is limited to +10% and Alice Clark 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. Richard Acklam: 92%, Alice Clark: 89%. Reduce level confidence based on how unexpected the result is. Richard Acklam: 48%, Alice Clark: 46%. A final adjustment of +0.2% 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 Alice Clark: 1,283, level confidence: 46%. Final level for Richard Acklam: 2,022, level confidence: 48%. Notes
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