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Login: | Explaining level changesDivision 2: University of Bath Ladies A v Kingsdown (Thu 10 Nov 2022)Match played between Thea Morgan (home) and Sarah Gillies (away).Match won by Thea Morgan. Result: 15-12,15-10,16-14. Starting level for Thea Morgan: 190, level confidence: 43%. Starting level for Sarah Gillies: 538, level confidence: 22%. Sarah Gillies to win as she is currently playing 183% better than Thea Morgan. Thea Morgan won all of the games and 56% 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 28% (PAR scoring). These are weighted and combined to calculate that Thea Morgan played 37% better than Sarah Gillies in this match. An upset! Assuming that any level changes are shared between both players, for this result it looks like Thea Morgan actually played at a level of 374 and Sarah Gillies at a level of 273. Without any damping, both players would need to be adjusted by 97% to match this result. Allowing for the difference in level between the players, the adjustments have been reduced to 50% and 50% respectively. Factoring in the relative levels of confidence which allows players with low confidence in their levels to change more quickly, the adjustment for Thea Morgan changes to +25% and Sarah Gillies changes to -50%. After applying standard match damping, the adjustment for Thea Morgan becomes +13.5% and for Sarah Gillies becomes -24%. Apply match/event weighting of 75% for 'Womens Autumn 2022/2023' so the adjustment for Thea Morgan is +10.1% and for Sarah Gillies is -17%. 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 Sarah Gillies is limited to -9.7% 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. Thea Morgan: 66%, Sarah Gillies: 47%. Reduce level confidence based on how unexpected the result is. Thea Morgan: 33%, Sarah Gillies: 24%. A final adjustment of +3.1% 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 Thea Morgan: 219, level confidence: 33%. Final level for Sarah Gillies: 497, level confidence: 24%. Notes
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