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Login: | Explaining level changesAndrew McKelvey v Sarah Trevelyan (Wed 15 May 2024)Match won by Sarah Trevelyan. Result: 11-15,6-15,4-15.Starting level for Andrew McKelvey: 203, level confidence: 77%. Set manually. Starting level for Sarah Trevelyan: 732, level confidence: 79%. Set manually. Sarah Trevelyan to win as she is currently playing 261% better than Andrew McKelvey. Sarah Trevelyan won all of the games and 68% 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 114% (PAR scoring). These are weighted and combined to calculate that Sarah Trevelyan played 114% better than Andrew McKelvey in this match. Due to the difference between the players' levels, allow for the likelihood that Sarah Trevelyan was taking it easy by anything up to 31%. This gives her an allowed level range for this match between 293 and 732 without affecting her level. In this case, Sarah Trevelyan played at level 470 and remained within her allowed range so her level will not be adjusted. On the assumption that Sarah Trevelyan would normally have been playing at level 507 (based on typical behaviour), Andrew McKelvey played better than expected and therefore gains a pre-damping level increase of 8%. Allowing for the difference in level between the players, including some additional protection for the better player, the adjustments have been reduced to 0% and 4.1% respectively. Factoring in the relative levels of confidence which allows players with low confidence in their levels to change more quickly, the adjustment for Sarah Trevelyan changes to 0% and Andrew McKelvey changes to +4.1%. After applying standard match damping, the adjustment for Sarah Trevelyan becomes 0% and for Andrew McKelvey becomes +3.6%. Apply match/event weighting of 50% for 'Westbury David Lloyd Boxes' so the adjustment for Sarah Trevelyan is 0% and for Andrew McKelvey is +1.8%. Increase level confidence due to one more match played. Sarah Trevelyan: 89%, Andrew McKelvey: 87%. Reduce level confidence based on how unexpected the result is. Sarah Trevelyan: 69%, Andrew McKelvey: 67%. 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 Andrew McKelvey: 207, level confidence: 67%. Final level for Sarah Trevelyan: 734, level confidence: 69%. Notes
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