|
Menu
Login: | Explaining level changesGary Birchall v Meg Lane (Wed 17 May 2017)Match won by Meg Lane. Result: 2-9,9-7,1-9,2-9.Starting level for Gary Birchall: 222, level confidence: 56%. Starting level for Meg Lane: 448, level confidence: 50%. Meg Lane to win as she is currently playing 102% better than Gary Birchall. Meg Lane won 75% of the games and 71% 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 58% (english scoring). These are weighted and combined to calculate that Meg Lane played 36% better than Gary Birchall in this match. Due to the difference between the players' levels, allow for the likelihood that Meg Lane was taking it easy by anything up to 13%. This gives her an allowed level range for this match between 320 and 448 without affecting her level. As Meg Lane has played below her allowed range at 311, her level reduction is 2.9% before damping. On the assumption that Meg Lane would normally have been playing at level 391 (based on typical behaviour), Gary Birchall played better than expected and therefore gains a pre-damping level increase of 14%. Allowing for the difference in level between the players, the adjustments have been reduced to 2.1% and 9.6% respectively. Factoring in the relative levels of confidence which allows players with low confidence in their levels to change more quickly, the adjustment for Meg Lane changes to -2.1% and Gary Birchall changes to +8.6%. After applying standard match damping, the adjustment for Meg Lane becomes -2.1% and for Gary Birchall becomes +5.8%. Apply match/event weighting of 50% for 'Weston Club Boxes' so the adjustment for Meg Lane is -1% and for Gary Birchall is +2.9%. As Gary Birchall has a provisional level, this match has been used to calibrate her level so Meg Lane's level has been left unchanged. Increase level confidence due to one more match played. Meg Lane: 71%, Gary Birchall: 75%. Reduce level confidence based on how unexpected the result is. Meg Lane: 58%, Gary Birchall: 61%. A final adjustment of -1.1% 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 Gary Birchall: 229, level confidence: 61%. Final level for Meg Lane: 436, level confidence: 58%. Notes
|