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Login: | Explaining level changesRuth Drysdale v Mark Thorne (Sat 24 Feb 2024)Match won by Ruth Drysdale. Result: 15-8,15-11,13-15,15-13.Starting level for Ruth Drysdale: 529, level confidence: 65%. Starting level for Mark Thorne: 1,097, level confidence: 26%. Mark Thorne to win as he is currently playing 107% better than Ruth Drysdale. Ruth Drysdale won 75% of the games and 55% of the points. This games result would be expected if she was better by around 25%. This points result would be expected if she was better by around 23% (PAR scoring). These are weighted and combined to calculate that Ruth Drysdale played 24% better than Mark Thorne in this match. An upset! Assuming that any level changes are shared between both players, for this result it looks like Ruth Drysdale actually played at a level of 850 and Mark Thorne at a level of 683. Without any damping, both players would need to be adjusted by 61% to match this result. Allowing for the difference in level between the players, including some additional protection for the better player, the adjustments have been reduced to 39% and 32% respectively. Factoring in the relative levels of confidence which allows players with low confidence in their levels to change more quickly, the adjustment for Ruth Drysdale changes to +15% and Mark Thorne changes to -32%. After applying standard match damping, the adjustment for Ruth Drysdale becomes +9% and for Mark Thorne becomes -16%. Apply match/event weighting of 50% for 'Redland Green Boxes' so the adjustment for Ruth Drysdale is +4.5% and for Mark Thorne is -7.4%. 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 Mark Thorne 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. Ruth Drysdale: 81%, Mark Thorne: 51%. Reduce level confidence based on how unexpected the result is. Ruth Drysdale: 50%, Mark Thorne: 31%. 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 Ruth Drysdale: 552, level confidence: 50%. Final level for Mark Thorne: 1,057, level confidence: 31%. Notes
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