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Login: | Explaining level changesDivision 2: Kingsdown v University of Bristol Chicken Dinners (Thu 25 Apr 2024)Match played between Pauline Butcher (home) and Zara 'Fresher' Long (away).Match won by Pauline Butcher. Result: 15-2,15-3,15-4. Starting level for Pauline Butcher: 337, level confidence: 83%. Set manually. Starting level for Zara 'Fresher' Long: 163, level confidence: 70%. Set manually. Pauline Butcher to win as she is currently playing 107% better than Zara 'Fresher' Long. Pauline Butcher won all of the games and 83% 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 400% (PAR scoring). These are weighted and combined to calculate that Pauline Butcher played 400% better than Zara 'Fresher' Long 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 524 and Zara 'Fresher' Long at a level of 105. Without any damping, both players would need to be adjusted by 56% to match this result. Allowing for the difference in level between the players, the adjustments have been reduced to 35% and 36% 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 +30% and Zara 'Fresher' Long changes to -36%. After applying standard match damping, the adjustment for Pauline Butcher becomes +15.6% and for Zara 'Fresher' Long becomes -18%. Apply match/event weighting of 75% for 'Womens Womans Spring 2023/2024' so the adjustment for Pauline Butcher is +12% and for Zara 'Fresher' Long 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 Pauline Butcher is limited to +10% and Zara 'Fresher' Long 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: 91%, Zara 'Fresher' Long: 84%. Reduce level confidence based on how unexpected the result is. Pauline Butcher: 58%, Zara 'Fresher' Long: 54%. Final level for Pauline Butcher: 371, level confidence: 58%. Final level for Zara 'Fresher' Long: 148, level confidence: 54%. Notes
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