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Login: | Explaining level changesPremier C: Westbury David Lloyd A v University of Bristol Chiefs (Wed 07 Dec 2016)Match played between Richard Dodsworth (home) and Jack Roddan (away).Match won by Jack Roddan. Result: 7-9,2-9,2-9. Starting level for Richard Dodsworth: 3,165, level confidence: 70%. Starting level for Jack Roddan: 2,449, level confidence: 66%. Richard Dodsworth to win as he is currently playing 29% better than Jack Roddan. Jack Roddan won all of the games and 71% of the points. This games result would be expected if he was better by around 55% or more. This points result would be expected if he was better by around 58% (english scoring). These are weighted and combined to calculate that Jack Roddan played 57% better than Richard Dodsworth in this match. An upset! Assuming that any level changes are shared between both players, for this result it looks like Jack Roddan actually played at a level of 3,489 and Richard Dodsworth at a level of 2,222. Without any damping, both players would need to be adjusted by 42% to match this result. Allowing for the difference in level between the players, the adjustments have been reduced to 37% and 37% respectively. Factoring in the relative levels of confidence which allows players with low confidence in their levels to change more quickly, the adjustment for Jack Roddan changes to +37% and Richard Dodsworth changes to -34%. After applying standard match damping, the adjustment for Jack Roddan becomes +13.1% and for Richard Dodsworth becomes -11%. Apply match/event weighting of 75% for 'Mixed Autumn 2016/2017' so the adjustment for Jack Roddan is +9.8% and for Richard Dodsworth is -8.3%. 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 Richard Dodsworth 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. Jack Roddan: 81%, Richard Dodsworth: 84%. Reduce level confidence based on how unexpected the result is. Jack Roddan: 57%, Richard Dodsworth: 59%. 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 Richard Dodsworth: 3,010, level confidence: 59%. Final level for Jack Roddan: 2,685, level confidence: 57%. Notes
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