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Login: | Explaining level changesDivision 2: Chippenham Olympiad A v University of Bath Ladies B (Thu 11 Nov 2021)Match played between Lara Sherwood (home) and Annabel Biggs (away).Match won by Annabel Biggs. Result: 10-15,15-11,13-15,18-20:6-15,12-15,15-12,15-12,15-7:15-11,15-11,15-7:15-5,15-9,15-4. Starting level for Lara Sherwood: 507, level confidence: 63%. Starting level for Annabel Biggs: 175, level confidence: 31%. Lara Sherwood to win as she is currently playing 190% better than Annabel Biggs. Annabel Biggs won 75% of the games and 52% 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 9% (PAR scoring). These are weighted and combined to calculate that Annabel Biggs played 20% better than Lara Sherwood in this match. Assuming that any level changes are shared between both players, for this result it looks like Annabel Biggs actually played at a level of 326 and Lara Sherwood at a level of 272. Without any damping, both players would need to be adjusted by 86% to match this result. Allowing for the difference in level between the players, the adjustments have been reduced to 44% and 44% respectively. Factoring in the relative levels of confidence which allows players with low confidence in their levels to change more quickly, the adjustment for Annabel Biggs changes to +44% and Lara Sherwood changes to -18%. After applying standard match damping, the adjustment for Annabel Biggs becomes +21.8% and for Lara Sherwood becomes -10.2%. Apply match/event weighting of 75% for 'Womens Ladies Autumn 2021/2022' so the adjustment for Annabel Biggs is +16% and for Lara Sherwood is -7.5%. 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 Annabel Biggs is limited to +10% and 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. Annabel Biggs: 56%, Lara Sherwood: 79%. Reduce level confidence based on how unexpected the result is. Annabel Biggs: 30%, Lara Sherwood: 42%. A final adjustment of -3.1% 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 Lara Sherwood: 482, level confidence: 42%. Final level for Annabel Biggs: 182, level confidence: 30%. Notes
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