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Login: | Explaining level changesMark Beech v Paul Ellis (Fri 18 Aug 2017)Match won by Paul Ellis. Result: 2-9,3-9,3-9.Starting level for Mark Beech: 820, level confidence: 50%. Starting level for Paul Ellis: 294, level confidence: 26%. Mark Beech to win as he is currently playing 179% better than Paul Ellis. Paul Ellis won all of the games and 77% 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 86% (english scoring). These are weighted and combined to calculate that Paul Ellis played 86% better than Mark Beech in this match. An upset! Assuming that any level changes are shared between both players, for this result it looks like Paul Ellis actually played at a level of 670 and Mark Beech at a level of 360. Without any damping, both players would need to be adjusted by 128% to match this result. Allowing for the difference in level between the players, the adjustments have been reduced to 64% and 64% respectively. Factoring in the relative levels of confidence which allows players with low confidence in their levels to change more quickly, the adjustment for Paul Ellis changes to +64% and Mark Beech changes to -26%. After applying standard match damping, the adjustment for Paul Ellis becomes +29.9% and for Mark Beech becomes -14%. Apply match/event weighting of 50% for 'Redland Green Boxes' so the adjustment for Paul Ellis is +15% and for Mark Beech is -6.4%. 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 Paul Ellis is limited to +10% 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. Paul Ellis: 51%, Mark Beech: 71%. Reduce level confidence based on how unexpected the result is. Paul Ellis: 22%, Mark Beech: 31%. A final adjustment of +1.8% 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 Mark Beech: 796, level confidence: 31%. Final level for Paul Ellis: 324, level confidence: 22%. Notes
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