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Login: | Explaining level changesDivision 3: Redwood v Chippenham Olympiad A (Thu 27 Feb 2014)Match played between Jane Barker (home) and Carol Cradock (away).Match won by Carol Cradock. Result: 0-9,3-9,9-7,8-10. Starting level for Jane Barker: 277, level confidence: 54%. Starting level for Carol Cradock: 229, level confidence: 60%. Jane Barker to win as she is currently playing 21% better than Carol Cradock. Carol Cradock won 75% of the games and 64% 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 35% (english scoring). These are weighted and combined to calculate that Carol Cradock played 28% better than Jane Barker in this match. Assuming that any level changes are shared between both players, for this result it looks like Carol Cradock actually played at a level of 285 and Jane Barker at a level of 222. Without any damping, both players would need to be adjusted by 25% to match this result. Factoring in the relative levels of confidence which allows players with low confidence in their levels to change more quickly, the adjustment for Carol Cradock changes to +20% and Jane Barker changes to -22%. After applying standard match damping, the adjustment for Carol Cradock becomes +11.2% and for Jane Barker becomes -12%. Apply match/event weighting of 75% for 'Womens Women's Spring 2013/2014' so the adjustment for Carol Cradock is +8.4% and for Jane Barker is -8.9%. 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 Jane Barker 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. Carol Cradock: 77%, Jane Barker: 74%. Reduce level confidence based on how unexpected the result is. Carol Cradock: 62%, Jane Barker: 59%. 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 Jane Barker: 263, level confidence: 59%. Final level for Carol Cradock: 248, level confidence: 62%. Notes
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