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Login: | Explaining level changesDivision 2: Kingsdown v University of Bath Ladies B (Thu 09 Feb 2023)Match played between Sarah Gillies (home) and Ellie Kaminska (away).Match won by Ellie Kaminska. Result: 15-7,12-15,9-15,19-17,11-15. Starting level for Sarah Gillies: 497, level confidence: 17%. Starting level for Ellie Kaminska: 270, level confidence: 19%. Sarah Gillies to win as she is currently playing 84% better than Ellie Kaminska. Ellie Kaminska won 60% of the games and 51% of the points. This games result would be expected if she was better by around 10%. This points result would be expected if she was better by around 5% (PAR scoring). These are weighted and combined to calculate that Ellie Kaminska played 9% better than Sarah Gillies in this match. Assuming that any level changes are shared between both players, for this result it looks like Ellie Kaminska actually played at a level of 382 and Sarah Gillies at a level of 351. Without any damping, both players would need to be adjusted by 41% 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 Ellie Kaminska changes to +25% and Sarah Gillies changes to -29%. After applying standard match damping, the adjustment for Ellie Kaminska becomes +13.5% and for Sarah Gillies becomes -15%. Apply match/event weighting of 75% for 'Womens Womans Spring 2022/2023' so the adjustment for Ellie Kaminska is +10.1% and for Sarah Gillies 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 Sarah Gillies 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. Ellie Kaminska: 44%, Sarah Gillies: 41%. Reduce level confidence based on how unexpected the result is. Ellie Kaminska: 31%, Sarah Gillies: 29%. 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 Sarah Gillies: 451, level confidence: 29%. Final level for Ellie Kaminska: 297, level confidence: 31%. Notes
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