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Login: | Explaining level changesDivision 1B: Lansdown 2 v University of Bath 1 (Wed 27 Oct 2010)Match played between Grant Jones (home) and Alex Melkonian (away).Match won by Alex Melkonian. Result: 9-7,8-10,9-5,6-9,1-9. Starting level for Grant Jones: 1,667, level confidence: 63%. Starting level for Alex Melkonian: 1,018, level confidence: 52%. Grant Jones to win as he is currently playing 64% better than Alex Melkonian. Alex Melkonian won 60% of the games and 55% 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% (english scoring). These are weighted and combined to calculate that Alex Melkonian played 10% better than Grant Jones in this match. Assuming that any level changes are shared between both players, for this result it looks like Alex Melkonian actually played at a level of 1,368 and Grant Jones at a level of 1,241. Without any damping, both players would need to be adjusted by 34% to match this result. Allowing for the difference in level between the players, the adjustments have been reduced to 26% and 26% respectively. Factoring in the relative levels of confidence which allows players with low confidence in their levels to change more quickly, the adjustment for Alex Melkonian changes to +26% and Grant Jones changes to -20%. After applying standard match damping, the adjustment for Alex Melkonian becomes +13.8% and for Grant Jones becomes -9.3%. Apply match/event weighting of 75% for 'Mixed Autumn 2010' so the adjustment for Alex Melkonian is +10.3% and for Grant Jones is -6.8%. 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 Grant Jones 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. Alex Melkonian: 72%, Grant Jones: 79%. Reduce level confidence based on how unexpected the result is. Alex Melkonian: 54%, Grant Jones: 59%. A final adjustment of +0.3% 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 Grant Jones: 1,592, level confidence: 59%. Final level for Alex Melkonian: 1,123, level confidence: 54%. Notes
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