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Login: | Explaining level changesAlex Williams v Pauline Butcher (Tue 24 May 2022)Match won by Alex Williams. Result: 9-1,9-3,8-10,9-5.Starting level for Alex Williams: 808, level confidence: 78%. Set manually. Starting level for Pauline Butcher: 418, level confidence: 73%. Set manually. Alex Williams to win as he is currently playing 93% better than Pauline Butcher. Alex Williams won 75% of the games and 65% of the points. This games result would be expected if he was better by around 25%. This points result would be expected if he was better by around 38% (english scoring). These are weighted and combined to calculate that Alex Williams played 29% better than Pauline Butcher in this match. Due to the difference between the players' levels, allow for the likelihood that Alex Williams was taking it easy by anything up to 11%. This gives him an allowed level range for this match between 600 and 808 without affecting his level. As Alex Williams has played below his allowed range at 569, his level reduction is 5.3% before damping. On the assumption that Alex Williams would normally have been playing at level 717 (based on typical behaviour), Pauline Butcher played better than expected and therefore gains a pre-damping level increase of 15%. Allowing for the difference in level between the players, the adjustments have been reduced to 3.8% and 10.7% respectively. Factoring in the relative levels of confidence which allows players with low confidence in their levels to change more quickly, the adjustment for Alex Williams changes to -3.6% and Pauline Butcher changes to +10.7%. After applying standard match damping, the adjustment for Alex Williams becomes -3.3% and for Pauline Butcher becomes +6.8%. Apply match/event weighting of 50% for 'Kingsdown & Horfield Boxes' so the adjustment for Alex Williams is -1.6% and for Pauline Butcher is +3.4%. Increase level confidence due to one more match played. Alex Williams: 88%, Pauline Butcher: 85%. Reduce level confidence based on how unexpected the result is. Alex Williams: 72%, Pauline Butcher: 70%. 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 Alex Williams: 794, level confidence: 72%. Final level for Pauline Butcher: 432, level confidence: 70%. Notes
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