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Login: | Explaining level changesDivision 2: Chippenham Olympiad A v Kingsdown (Thu 18 Nov 2021)Match played between Emma Alexander (home) and Mary Walkerdine (away).Match won by Emma Alexander. Result: 15-5,15-4,15-3. Starting level for Emma Alexander: 240, level confidence: 71%. Set manually. Starting level for Mary Walkerdine: 138, level confidence: 61%. Emma Alexander to win as she is currently playing 74% better than Mary Walkerdine. Emma Alexander won all of the games and 79% 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 275% (PAR scoring). These are weighted and combined to calculate that Emma Alexander played 275% better than Mary Walkerdine in this match. Assuming that any level changes are shared between both players, for this result it looks like Emma Alexander actually played at a level of 352 and Mary Walkerdine at a level of 94. Without any damping, both players would need to be adjusted by 47% 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 +29% and Mary Walkerdine changes to -34%. After applying standard match damping, the adjustment for Emma Alexander becomes +15.4% and for Mary Walkerdine becomes -17%. Apply match/event weighting of 75% for 'Womens Ladies Autumn 2021/2022' so the adjustment for Emma Alexander is +12% and for Mary Walkerdine is -13%. 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 Emma Alexander is limited to +10% and Mary Walkerdine 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: 84%, Mary Walkerdine: 78%. Reduce level confidence based on how unexpected the result is. Emma Alexander: 57%, Mary Walkerdine: 53%. Final level for Emma Alexander: 264, level confidence: 57%. Final level for Mary Walkerdine: 131, level confidence: 53%. Notes
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