With the end of the regular season it's time to think about who the statistical leaders were in the WNBA, and one of the best stats to look at is John Hollinger's Player Efficiency Rating, or PER.  We wrote about PER in 2009 (but for those who don't know how it works, you can click the article link and find out.  So which players this year had the best Player Efficiency Rating?

For those who have a broken click finger, PER is an "all-in-one" metric:  it attempts to quantify everything a player has done for the season in one number with all of the advantages (simplicity) and disadvantages (loss of information) associated with single-number metrics.  A great advantage in using PER is that it is not an additive metric - you can't benefit from your team playing at a faster pace than the average team.  PER doesn't depend on how many minutes you play or how many shots you get to take.  Team pace and other situation-dependent factors are built into PER. 

The calculation of PER is normalized to set the league average player at 15.00.  This allows us to compare different players in different seasons playing different games with different kinds of teams.  Furthermore, one can look at PER and decipher the meaning very quickly:  30.00 is really great, 15.00 is average.  Hollinger provides a scale to use with PER:

A year for the ages: 35.0
Runaway MVP candidate: 30.0
Strong MVP candidate: 27.5
Weak MVP candidate: 25.0
Bona fide All-Star: 22.5
Borderline All-Star: 20.0
Solid 2nd option: 18.0
3rd Banana: 16.5
Pretty good player: 15.0
In the rotation: 13.0
Scrounging for minutes: 11.0
Definitely renting: 9.0
Next stop: Latvia: 5.0

So what can PER tell us about the 2010 season?

The first thing we learn is that there is a statistical tie for MVP.  Lauren Jackson, Sylvia Fowles and Tamika Catchings (*) are in a statistical dead-heat.  If I had to assign an MVP based on PER alone, I'd give the MVP to Catchings because one problem with stats is that they don't adequately capture a player's defensive contributions and Catchings is known to be one of the great defenders.

Tina Charles definitely had a great rookie season.  Not at the 2008 Candace Parker level, but she was within the periphery of MVP consideration.  Charles, according to PER, is the Rookie of the Year in 2010.  You didn't need a metric to figure that out.

One can amuse one's self by evaluating trades with PER:  simply evaluate a player's PER value before the trade, and evaluate it after.  The PER values presented below are for the entire season, but when a player plays on two different teams in a season, we only have the PER values associated with each of the separate teams.  The separate team values are weighted by minutes played to give a cumulative PER, but taking PER values for each of the teams she played for before and after a trade can be a useful exercise. 

Let's look at Tulsa, for example.  Tulsa traded Plenette Pierson for Tiffany Jackson.  Let's look at the PERs associated with the player tenures.

Plenette Pierson had a PER of 17.12 with Tulsa...but one of 28.96 with New York.  Tiffany Jackson's PER was 12.79 with New York...and stayed pretty much the same in Tulsa with 12.81.  It looks like that trade was pretty much a no-brainer for New York.

There should be one value on this list that's quite surprising - that of Marion Jones.  Jones averaged 3.4 points per game for the Shock, and most people have figured "one and done". However, word in Tulsa is that Jones will be hanging around next season.  Her PER value is an astonishing 15.88, making her an average player in PER's reckoning.  Part of that probably comes from her 52.5 percent field goal percentage.  (Any question regarding Marion Jones's PER value should be sent to John Hollinger who can be reached via Twitter.  The results were obtained using WNBA stats but were not calculated by Mr. Hollinger.)

(*) - Why is Jessica Adair so high on this list?  Remember, PER isn't an additive metric.  She only played 14 minutes this year, but PER realllly liked those 14 minutes.  If she played 140 minutes her PER might possibly be lower.