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Login: | Explaining level changesDivision 2: University of Bath Ladies B v Kingsdown (Thu 20 Apr 2023)Match played between Lily Jackson (home) and Pauline Butcher (away).Match won by Pauline Butcher. Result: 6-15,6-15,5-15. Starting level for Lily Jackson: 251, level confidence: 53%. Starting level for Pauline Butcher: 359, level confidence: 61%. Pauline Butcher to win as she is currently playing 43% better than Lily Jackson. Pauline Butcher won all of the games and 73% of the points. This games result would be expected if she was better by around 55% or more. This points result would be expected if she was better by around 165% (PAR scoring). These are weighted and combined to calculate that Pauline Butcher played 165% better than Lily Jackson in this match. Assuming that any level changes are shared between both players, for this result it looks like Pauline Butcher actually played at a level of 488 and Lily Jackson at a level of 185. Without any damping, both players would need to be adjusted by 36% 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 Pauline Butcher changes to +25% and Lily Jackson changes to -29%. After applying standard match damping, the adjustment for Pauline Butcher becomes +13.7% and for Lily Jackson becomes -15%. Apply match/event weighting of 75% for 'Womens Womans Spring 2022/2023' so the adjustment for Pauline Butcher is +10.3% and for Lily Jackson is -11%. 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 Lily Jackson is limited to -10% 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. Pauline Butcher: 78%, Lily Jackson: 73%. Reduce level confidence based on how unexpected the result is. Pauline Butcher: 57%, Lily Jackson: 53%. A final adjustment of -0.1% 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 Lily Jackson: 228, level confidence: 53%. Final level for Pauline Butcher: 394, level confidence: 57%. Notes
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