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Login: | Explaining level changesDivision 2: Chippenham Olympiad A v University of Bristol Beasts (Thu 02 Dec 2021)Match played between Lara Sherwood (home) and Holly Ashall (away).Match won by Holly Ashall. Result: 9-15,12-15:6-15,4-15,4-15:11-15,15-6,15-8,15-12:15-13,15-11,10-15,9-15,12-15. Starting level for Lara Sherwood: 475, level confidence: 56%. Starting level for Holly Ashall: 396, level confidence: 71%. Set manually. Lara Sherwood to win as she is currently playing 20% better than Holly Ashall. Holly Ashall won all of the games and 59% 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 43% (PAR scoring). These are weighted and combined to calculate that Holly Ashall played 47% better than Lara Sherwood in this match. Assuming that any level changes are shared between both players, for this result it looks like Holly Ashall actually played at a level of 526 and Lara Sherwood at a level of 358. Without any damping, both players would need to be adjusted by 33% to match this result. As this is a best of 3 match rather than best of 5, these adjustments have been reduced to 21% and 21% respectively. Factoring in the relative levels of confidence which allows players with low confidence in their levels to change more quickly, the adjustment for Holly Ashall changes to +17% and Lara Sherwood changes to -21%. After applying standard match damping, the adjustment for Holly Ashall becomes +9.7% and for Lara Sherwood becomes -12%. Apply match/event weighting of 75% for 'Womens Ladies Autumn 2021/2022' so the adjustment for Holly Ashall is +7.3% and for Lara Sherwood is -8.6%. 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 Lara Sherwood 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. Holly Ashall: 84%, Lara Sherwood: 75%. Reduce level confidence based on how unexpected the result is. Holly Ashall: 64%, Lara Sherwood: 57%. A final adjustment of -2.9% 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 Lara Sherwood: 452, level confidence: 57%. Final level for Holly Ashall: 401, level confidence: 64%. Notes
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