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Login: | Explaining level changesDivision 2: Chippenham Olympiad A v University of Bath Ladies B (Thu 02 May 2024)Match played between Emma Alexander (home) and Abi Scott (away).Match won by Emma Alexander. Result: 15-9,15-11,9-15,15-12. Starting level for Emma Alexander: 305, level confidence: 47%. Starting level for Abi Scott: 548, level confidence: 22%. Abi Scott to win as she is currently playing 80% better than Emma Alexander. Emma Alexander won 75% of the games and 53% 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 15% (PAR scoring). These are weighted and combined to calculate that Emma Alexander played 22% better than Abi Scott in this match. An upset! Assuming that any level changes are shared between both players, for this result it looks like Emma Alexander actually played at a level of 451 and Abi Scott at a level of 371. Without any damping, both players would need to be adjusted by 48% to match this result. Allowing for the difference in level between the players, the adjustments have been reduced to 34% and 34% respectively. Factoring in the relative levels of confidence which allows players with low confidence in their levels to change more quickly, the adjustment for Emma Alexander changes to +16% and Abi Scott changes to -34%. After applying standard match damping, the adjustment for Emma Alexander becomes +9.2% and for Abi Scott becomes -17%. Apply match/event weighting of 75% for 'Womens Womans Spring 2023/2024' so the adjustment for Emma Alexander is +6.9% and for Abi Scott is -12%. 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 Abi Scott 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. Emma Alexander: 68%, Abi Scott: 47%. Reduce level confidence based on how unexpected the result is. Emma Alexander: 46%, Abi Scott: 32%. 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 Emma Alexander: 326, level confidence: 46%. Final level for Abi Scott: 521, level confidence: 32%. Notes
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