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Login: | Explaining level changesDivision 3: Whitchurch Imperial A v Lansdown 4 (Wed 04 May 2022)Match played between Bill Hope (home) and Laurie Willis (away).Match won by Laurie Willis. Result: 6-15,7-15,7-15:6-15,15-5,14-16,13-15:13-15,9-15,9-15:9-15,4-15,7-15:15-10,8-15,10-15,12-15. Starting level for Bill Hope: 1,243, level confidence: 87%. Set manually. Starting level for Laurie Willis: 1,572, level confidence: 68%. Laurie Willis to win as he is currently playing 26% better than Bill Hope. Laurie Willis won all of the games and 69% 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 125% (PAR scoring). These are weighted and combined to calculate that Laurie Willis played 125% better than Bill Hope in this match. Assuming that any level changes are shared between both players, for this result it looks like Laurie Willis actually played at a level of 2,097 and Bill Hope at a level of 932. Without any damping, both players would need to be adjusted by 33% to match this result. Allowing for the difference in level between the players, the adjustments have been reduced to 29% and 29% respectively. Factoring in the relative levels of confidence which allows players with low confidence in their levels to change more quickly, the adjustment for Laurie Willis changes to +29% and Bill Hope changes to -22%. After applying standard match damping, the adjustment for Laurie Willis becomes +12.7% and for Bill Hope becomes -10.9%. Apply match/event weighting of 75% for 'Mixed Spring 2021/2022' so the adjustment for Laurie Willis is +9.5% and for Bill Hope is -7.9%. 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 Bill Hope 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. Laurie Willis: 82%, Bill Hope: 93%. Reduce level confidence based on how unexpected the result is. Laurie Willis: 62%, Bill Hope: 70%. 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 Bill Hope: 1,182, level confidence: 70%. Final level for Laurie Willis: 1,719, level confidence: 62%. Notes
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