I dont think the subsequent comments relating to this question are correct.TomChivers wrote:So if an improving junior graded 100 has a season consisting of beating me 30 times, his grade will be 190 only. Yet clearly his grade should be higher than mine, i.e. over 200.
Previous to 2009 an ungraded junior would have been graded 260 taking your previous grade as 200. I pointed this out and several other anomalies during the 2009 rehash and I think the basis was changed so that the junior would be 250.
Since 2009 juniors, who have played more than 20 games, as in your example are treated as ungraded so his new grade would be 250 most likely or possibly 260.
The basis of grading juniors is not clear in the documentation produced after the 2009 rehash, and if you burrow into the calculations for juniors along the way you can have a discussion with Roger de C about lack of stability over time and Brian Valentine about whether start values are needed in the markov process and a few other people who think that the ELO system solves all the problems. Additionally arbiters seem to think that both systems predict results and justify the accelerated paring system in tournaments. Neither system is based on any concrete mathematics and thus are approximations to a goal which can never be achieved.
Even the name is approximately referred to as the Clarke BCF/ECF grading system, whereas in fact it was invented by a Scotsman Kenneth Harkness primarily for RR tournaments. Clarke instigated its approximate use for unbalanced leagues where players had different activity rates and, thus made the issues of deflation, stretch and local inertia more prominent. Cynics suggest that Harkness gave the ECF the grading system as a joke and later Scotland switched to an ELO based system but the ECF havent realised the joke yet. Perhaps this last point could be confirmed by Geoff Chandler who is an approximation to a Scotsman or Alex McFarlane who spends so much time over the boarder he could be considered as extrapolated English.