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Login: | Explaining level changesMichael Taylor v Pauline Butcher (Thu 18 May 2017)Match won by Michael Taylor. Result: 9-4,4-9,10-8,9-5.Starting level for Michael Taylor: 350, level confidence: 83%. Set manually. Starting level for Pauline Butcher: 450, level confidence: 69%. Pauline Butcher to win as she is currently playing 29% better than Michael Taylor. Michael Taylor 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 11% (english scoring). These are weighted and combined to calculate that Michael Taylor played 20% better than Pauline Butcher in this match. An upset! Assuming that any level changes are shared between both players, for this result it looks like Michael Taylor actually played at a level of 435 and Pauline Butcher at a level of 362. Without any damping, both players would need to be adjusted by 24% to match this result. Allowing for the difference in level between the players, the adjustments have been reduced to 21% and 21% respectively. Factoring in the relative levels of confidence which allows players with low confidence in their levels to change more quickly, the adjustment for Michael Taylor changes to +18% and Pauline Butcher changes to -21%. After applying standard match damping, the adjustment for Michael Taylor becomes +10% and for Pauline Butcher becomes -12%. Apply match/event weighting of 50% for 'Kingsdown & Horfield Boxes' so the adjustment for Michael Taylor is +5% and for Pauline Butcher is -5.6%. 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 Pauline Butcher 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. Michael Taylor: 91%, Pauline Butcher: 83%. Reduce level confidence based on how unexpected the result is. Michael Taylor: 73%, Pauline Butcher: 67%. A final adjustment of -2.1% 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 Michael Taylor: 366, level confidence: 73%. Final level for Pauline Butcher: 414, level confidence: 67%. Notes
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