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Login: | Explaining level changesDivision 1: Thornbury A (Summer) v Weston String Strokers (Wed 20 Jul 2022)Match played between Vivi B (home) and Dan Tripp (away).Match won by Dan Tripp. Result: 15-8,15-13,15-17,8-15,8-15. Starting level for Vivi B: 2,074, level confidence: 65%. Starting level for Dan Tripp: 1,443, level confidence: 68%. Vivi B to win as he is currently playing 44% better than Dan Tripp. Dan Tripp won 60% of the games and 53% of the points. This games result would be expected if he was better by around 10%. This points result would be expected if he was better by around 11% (PAR scoring). These are weighted and combined to calculate that Dan Tripp played 10% better than Vivi B in this match. Assuming that any level changes are shared between both players, for this result it looks like Dan Tripp actually played at a level of 1,817 and Vivi B at a level of 1,647. Without any damping, both players would need to be adjusted by 26% to match this result. Allowing for the difference in level between the players, the 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 Dan Tripp changes to +20% and Vivi B changes to -21%. After applying standard match damping, the adjustment for Dan Tripp becomes +9.7% and for Vivi B becomes -8.8%. Apply match/event weighting of 65% for 'Mixed Summer 2022' so the adjustment for Dan Tripp is +6.3% and for Vivi B is -5.6%. 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 Vivi B 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. Dan Tripp: 82%, Vivi B: 80%. Reduce level confidence based on how unexpected the result is. Dan Tripp: 65%, Vivi B: 64%. A final adjustment of -0.2% 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 Vivi B: 1,972, level confidence: 64%. Final level for Dan Tripp: 1,531, level confidence: 65%. Notes
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