Comparison between ResultsZone and SquashLevels ranking

The following tables and plot compare the ranking points from ResultsZone (RZ) with the level from SquashLevels (SL) for the North West Counties Squash League (NWCSL) at mid 2018. The data were obtained from about twenty clubs in Merseyside and Cheshire. A trend was determined and used to produce the tables. The tables also show the percentage change in SL level that is equivalent to 100 points in RZ.
RZ points SL level SL % change
1000 215 12.4
1100 245 12.4
1200 275 12.4
1300 310 12.4
1400 345 12.4
1500 390 12.4
1600 440 12.4
1700 490 12.5
1800 550 12.8
1900 620 13.0
2000 710 13.2
2100 800 13.5
2200 900 13.7
2300 1040 14.0
2400 1180 14.3
2500 1360 14.6
     
RZ points SL level SL % change
2600 1560 14.9
2700 1780 15.2
2800 2060 15.6
2900 2400 16.0
3000 2750 16.5
3100 3250 16.9
3200 3800 17.4
3300 4500 18.0
3400 5300 18.7
3500 6300 19.3
3600 7500 20.0
3700 9000 20.5
3800 11000 20.5
3900 13200 20.5
4000 15800 20.5
4100 19000 20.5

The SL rankings are much more spread out compared to RZ at the high end. This is because SL works with ratios so that a percent change in SL corresponds to a fixed change in RZ. Even taking account of this, a difference of 100 points in RZ, corresponds to a difference of about 12% in SL at the low end but corresponds to 20% at the high end. This may be in part because the lower divisions use PARS to 15 while the higher divisions use PARS to 11. An unexpected win is more difficult in PARS to 15 compared to PARS to 11; thus RZ, which only uses win/loss to assign points, is more spread out for the lower divisions. RZ also changes its method of assigning points slightly at the high end. Neither system will be perfectly in sync across different divisions, and across tournament players in the case of SL.

Analysis and page by Ivan Baldry, programme leader for MSc Data Science at LJMU.