We received some worthwhile feedback on the initial post introducing these volleyball player rankings, and made a few changes explained below. (Refer to the original post for an explanation of the ranking system.)
Block assists and solo blocks now both count as one full block, on the advice of a reader (thanks, "Blocks and math"), rather than 0.5 and 1 respectively.
We then regressed each player's hitting percentage toward her conference average, to adjust somewhat for the small sample size. This generally did not make a large difference among those with many attempts, and didn't change much even for those a modest number (a change of 14 points at most for anyone with 100+ total attempts).
We also had to adjust the rescaling of the raw plus/minus so we could continue to express players' contributions in terms of matches above average (per 20 games). For some players, this resulted in a more conservative estimate of value. As an example, Nadine Alphonse went from 4.9 matches above average to 3.5, and Beth Clark dropped from 4.2 to 3.3. However, this rescaling does not affect the overall ordering of players (whereas the block correction did). If you prefer, you can just look at unadjusted points above average, which involves fewer assumptions and no rescaling; the ordering of the players will be the same either way.
These rankings are an ever-evolving entity, and consistent feedback and constructive criticism are greatly appreciated. We'd also like to caution you against reading too much into small differences due to the small sample of (at most) 20 games of data, and the uncertainties inherent in any CIS stat collection.
What do the new rankings look like?
As expected by our (mostly anonymous) reader, two of UBC's players rise in the rankings after we changed the block calculations. Instead of being sixth and (tied for) seventh, Jen Hinze (+2.6) and Kyla Richey (+2.6) are now both in the top five. The top three players remain the same: Alphonse (+3.5), Clark (+3.3), and Kristina Vleck (+2.8).
The first-team All-Canadians are 11th, 53rd, 7th, 29th, 1st, 3rd, and 116th. Rookie of the year Sonia Rossy (485th overall, 0.9 matches below average) shows how our choice to ignore digs influences these rankings: there certainly weren't 484 players in CIS better than her last year. Laurier's Julie Gordon was our top-ranked of the all-rookie team (45th, +1.1), for what it's worth.
And TWU's Lauren O'Reilly, off to the worlds in the fall as part of the Canadian senior team (the same side which just finished 7th at the Pan-Am Games), was 57th overall in CIS play in 2009-2010, worth about a win more than average.
You can view the complete rankings here.