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Login: | Explaining level changesDivision 2: University of Bristol Beasts v University of Bath Ladies A (Thu 14 Mar 2019)Match played between Maddie Freeman (home) and Georgia Mackenzie (away).Match won by Maddie Freeman. Result: 13-15,15-7,15-9,15-9:15-12,9-15,11-15,13-15:15-6,15-9,15-11:15-4,15-10,15-9:15-4,15-4,15-4. Starting level for Maddie Freeman: 514, level confidence: 62%. Starting level for Georgia Mackenzie: 642, level confidence: 46%. Georgia Mackenzie to win as he is currently playing 25% better than Maddie Freeman. Maddie Freeman won 75% of the games and 59% 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 45% (PAR scoring). These are weighted and combined to calculate that Maddie Freeman played 32% better than Georgia Mackenzie in this match. Assuming that any level changes are shared between both players, for this result it looks like Maddie Freeman actually played at a level of 659 and Georgia Mackenzie at a level of 501. Without any damping, both players would need to be adjusted by 28% to match this result. Allowing for the difference in level between the players, the adjustments have been reduced to 25% and 25% respectively. Factoring in the relative levels of confidence which allows players with low confidence in their levels to change more quickly, the adjustment for Maddie Freeman changes to +18% and Georgia Mackenzie changes to -25%. After applying standard match damping, the adjustment for Maddie Freeman becomes +10.4% and for Georgia Mackenzie becomes -13%. Apply match/event weighting of 75% for 'Womens Ladies Spring 2018/2019' so the adjustment for Maddie Freeman is +7.8% and for Georgia Mackenzie is -9.8%. 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 Georgia Mackenzie 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. Maddie Freeman: 79%, Georgia Mackenzie: 68%. Reduce level confidence based on how unexpected the result is. Maddie Freeman: 61%, Georgia Mackenzie: 53%. A final adjustment of +6% 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 Maddie Freeman: 541, level confidence: 61%. Final level for Georgia Mackenzie: 703, level confidence: 53%. Notes
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