2013 WNBA MVP rankings: How much does plus/minus matter in determining 'value'?

Candace Parker's combination of size, versatility and dunking ability just begs for the type of hyperbolic upside that former Los Angeles Sparks coach Michael Cooper bestowed upon her before she ever played a WNBA game.

"I liken Candace Parker to when the Lakers acquired Kareem Abdul-Jabbar and then in 1979 we acquired Magic Johnson and then in 1983-84 we acquired James Worthy. But we got all those three players in one on one day in one draft."

And that's not really establishing a high ceiling as much as a prophecy that is best delivered in tongues.

Indeed Parker's ability to do so many things made it easy to imagine her doing anything, before Cooper was even allowed to utter a word. Parker was the reason I began paying attention to and writing about the league - even if the prophecies were entirely unrealistic, it seemed something big was on the horizon.

But reality is that Parker could never live up to all that hype - no human being could, even in light of her winning Rookie of the Year, MVP and an Olympic gold medal in her first year as a pro. But is she really the clear choice for MVP that she's been made out to be this season?

Setting aside expectations, Parker is clearly one of the league's best players, she's having a great 2013 season, and her team could end up with the best record in the league at the end of the regular season. Yet calling her the clear frontrunner for the 2013 WNBA Most Valuable Player award, as we've heard from quite a few analysts throughout the season, might be a bit exaggerated.

To be clear, none of this is to negate the fact that Parker is a great player having a very good season. But some of the things that folks around here have been harping on all season - defense, position, and shot selection - do weaken her MVP argument a bit before getting to the statistics. Then there's one statistic that stands out as a big question mark: Parker has a net plus/minus rating of -1.6.

The MVP framework: How much does plus/minus really matter?

In short, the net plus/minus numbers made available by the Minnesota Lynx measure a player's impact on the floor by the difference between a team's offensive and defensive performance when a player is on or off the court. It's a metric that can be extremely noisy and generate some weird results even with more advanced methods like adjusted plus/minus or Regularized Adjusted Plus Minus, especially with small sample sizes (and, at 34 games, a WNBA season is a tiny sample size). Nevertheless, it tells a story especially for a player under consideration for a most valuable player award.

To be more specific, a negative net plus/minus rating indicates that when a player is off the floor their team scored more on a per minute basis. Setting aside the pitfalls of plus/minus, a negative rating should at the very least give reasons for pause before considering someone for the MVP award. Furthermore, given that the power of plus/minus improves with a larger sample size, the fact that she also had a negative rating last season (-5.2) means that there might be a pattern worthy of a closer look at work.

For Parker, the plus/minus problem lies on the defensive end: last season, the Sparks were 4.3 points better defensively with Parker off the floor; this season, the Sparks are 7.6 points better defensively with Parker off the floor. Without digging too deeply into what might be going on there statistically, those numbers are consistent with the critiques some WNBA fans make about Parker's defense.

But how much weight should we place on these numbers? Many others have discussed the pros and cons of using plus/minus - most notably 2013 NBA champion Miami Heat head coach Erik Spoelstra - and I've gone through the various methods for calculating it at length elsewhere so we won't dwell on the specifics for now except to say that they probably shouldn't be taken as gospel. As you'll see below, having an overwhelmingly positive plus/minus does not a MVP make: if we went strictly by plus/minus numbers, Minnesota Lynx center Janel McCarville would be the favorite for MVP with a +21 rating and, though she is important to Minnesota's success, it's probably fair to assume that it would be hard to find anyone to support that campaign.

Yet returning to a previous point, the numbers do help to tell a story or shape a narrative that can be useful in understanding a player's value to her team. Earlier in the season, I laid out a list of candidates based on the same framework that I've used in the past without using plus/minus simply because the sample size was so small. But the goal of using all these numbers is to find something concrete to define the nebulous construct of "value" that makes a player "most valuable". As described by Matt Moore of CBS Sports, there are multiple ways to define "value" - to the point that I quite liked the suggestion to break the MVP award into three parts - but I tend to think of it in terms of the player who is most indispensable to their team's success.

The Statistics

Although I look at multiple numbers when considering MVP candidates, I begin (naturally) with the MVP metric - "marginal victories produced" - first to sort out how stands out as the league's top players. After that I look at the other numbers described here to determine who has the strongest case for the award.

I've also included Ed Bemiss' "value" rating from National Sports Rankings - which essentially measures the percentage of an individual player's statistics relative to their team, similar conceptually to the WNBA's PIE statistic - just to offer a different perspective on things.

Player	Team	MVP	PVC	NSR value rating	Usage%	Pts/empty poss	Plus/minus
Angel McCoughtry	Atlanta Dream	13.81*	24.36	3.02	35.1*	1.88	+13.2
Sylvia Fowles	Chicago Sky	13.56	23.97	2.42	21.6	3.01*	+17.6
Tamika Catchings	Indiana Fever	12.98	25.17*	3.94*	29.20	2.1	+15.9
Maya Moore	Minnesota Lynx	12.69	21.19	2.57	23.2	2.82	+16.6
Erika de Souza	Atlanta Dream	11.64	20.53	1.13	18.4	2.6	+3.9
Candace Parker	Los Angeles Sparks	11.57	19.76	3.31	29.2	2.33	-1.3
Diana Taurasi	Phoenix Mercury	11.15	22.24	1.56	29.7	2.23	+10.2
Nneka Ogwumike	Los Angeles Sparks	10.9	18.62	1.3	22.7	2.83	+10.1
Tina Charles	Connecticut Sun	10.66	22.33	3.19	30.20	1.71	-12.1
Lindsay Whalen	Minnesota Lynx	10.37	17.32	0.77	24.9	2.18	+12.1
Danielle Robinson	San Antonio Silver Stars	9.95	23.38	1.62	19.5	1.66	+19.6 **
Elena Delle Donne	Chicago Sky	9.90	17.83	1.98	24.6	2.65	+13.9

Top 12 WNBA players ordered by MVP as of 8/18/13. Click here for more description of these numbers.
Click here for advanced statistics for the entire league.

12 is a sort of arbitrary number, obviously, but there's a reason I went that far: first, the league-leader in plus/minus happened to be number 11. Second, Elena Delle Donne's MVP number has been hurt due to her four-game injury absence so I added her to the list since she happened to be 12th and is a worthy candidate for discussion.

There are four players who stood out as having particularly strong arguments for the award, but first Parker's negative plus/minus probably demands a closer look.

Why does Candace Parker have a negative plus/minus?

Synergy Sports provides us with a simple explanation for Parker's negative plus/minus: her overall defensive rating is "poor" as of today.

The longer explanation: overall, Parker allows .939 points per possession (PPP) defensively, which is in the bottom 12% of the league. And unfortunately, it's much quicker to highlight what she's good at than highlight her weaknesses: according to Synergy, Parker is "good" at defending isolation plays from the top of the key (.917 PPP, 46th percentile) and "very good" at defending the post on the right block (.679 PPP, 78th percentile). In every other situation she's average or below.

Consistent with the dip in her plus/minus numbers, that's a major change from last year when Synergy rated her "excellent" overall (0.712 PPP) and excellent at defending spot ups (.757 PPP): this season, spot ups comprise 27.9% of her defensive situations and Synergy rates her as "poor" (1.174 PPP, 2nd percentile). The fact that she's also rated as "below average" in pick and roll situations pales in comparison to the spot up struggles.

Offensively, she's taking jumpers at higher rate this season (taking spot-up jumpers 13% of the time) but she's improved in transition to help her remain an "excellent" offensive player, which is reflected in a much improved offensive plus/minus. But the defensive picture created by her plus/minus and Synergy numbers make it very difficult to consider her the top candidate for the MVP award.

How do point guards fit?

I've long believed that the demands of the point guard position force us to evaluate point guards on a slightly different standard and by that standard Lindsay Whalen is putting together an outstanding season, beginning with her usage rate: Whalen currently has the highest usage rate on a very talented Lynx team in addition to maintaining the second-highest pure point rating in the league (5.4). But who does the best pure point rating (6.1) and plus/minus rating belong to? Danielle Robinson, who has certainly made her case to be seen as an elite WNBA point guard.

So what do we do with those players who rate just 10th and 11th on the list above by MVP? First, it's important to note why they're rated low: their primary strength is getting assists and keeping turnovers down, which aren't valued quite as heavily by that metric. And in Whalen's case, the fact that she is a high usage point guard adds a number of missed shots.

But here's the argument that should probably be considered for a player like Whalen moreso than Robinson, who is still a somewhat inefficient scorer: for a point guard to lead a team in usage rate and assist ratio means they're driving almost everything their team does. Although that doesn't result in the gaudy statistics that some other players possess, she distributes and scores so efficiently that she's placed herself in an extremely elite group historically - Sue Bird arguably had a better season in 2010, but otherwise it's hard to match what Whalen is doing this year. If Minnesota does finish the regular season as the top team in the league with Whalen posting numbers like these, how much should the fact that she's such a unique player playing at a high level figure into the discussion? That's something that reasonable people could probably disagree on so we'll move on for now.

Top MVP candidates

3. Sylvia Fowles, Chicago Sky: I've made the case for Fowles to win the award even when the Sky haven't been a playoff team so you can bet that I'm going to make the case that she's a strong candidate now. She has the fifth-best plus/minus in the league, is the most efficient scorer in the Eastern Conference (63.5%), and has the best offensive rebounding rate in the league (14.8%). Defensively, her team is 4.4 points better when she's on the floor, anchoring the paint for arguably the best defensive team in the Eastern Conference.

In other words, you'd have to make a pretty strong argument for someone else to not vote for Fowles. However, I think part of that argument for others lies in the narrative of the Sky's season: among players who play more than 10 minutes, Fowles has the third-highest usage rate on her team (21.6%) and by her own admission having some of the offensive pressure taken off of her this season has helped her perform. That's not at all a knock on Fowles as much a commentary on how this team functions: she has to share the credit offensively in a way that other candidates don't.

2. Tamika Catchings, Indiana Fever: My personal favorite candidate this season is Catchings and a large part of that is that I believe she not only has numbers on her side, but a pretty strong narrative. If the Fever finish third in the Eastern Conference, no matter how poorly the other teams have performed, somebody on that team needs to win an award, whether it be Lin Dunn winning Coach of the Year or Catchings winning MVP. The Fever easily could've given up on the season when the injuries started hitting them - and some other teams in the league essentially did - but they managed to remain competitive and have started winning without the help of All-Star Katie Douglas.

We could go through Catchings' statistics and they're impressive, as usual, but what can't get lost in this Fever season is her value as a leader on and off the court. There's so much said about that already that I'm not sure it needs to be reiterated here, but I think it's fair to assume that her locker room presence had something to do with the Fever being where they are right now. But if that's not enough, consider that Catchings has accounted for a league-high 25.17% of her team's overall statistical production (PVC), which could be taken as saying she does more for her team than anyone else.

1. Angel McCoughtry, Atlanta Dream: Although I do think Catchings has the narrative on her side right now, if the Dream manage to win the Eastern Conference with Tiffany Hayes and Sancho Lyttle each missing significant time this season, McCoughtry will have a pretty strong case for winning the award.

The Dream are a whopping 16.5 points better with McCoughtry on the court and, although her defensive numbers are a bit more modest, she can be the most disruptive player on the court at times by terrorizing opposing perimeter players in the passing lanes and blocking shots as a help defender.

But most of all, that McCoughtry has a 51.6% TS% - typically above average for a perimeter player - with the highest usage rate in the league is actually quite remarkable, despite not being the most efficient of her career. When compared to Catchings who has a 49.6% TS% at a lower usage rate, it arguably gives McCoughtry a leg up. That she has the highest MVP with a usage that high is also impressive: MVP normally works against volume shooters because it weights missed shots harshly but her ability to get to the line a bit helps. But that high MVP (and PVC) also reflects context: McCoughtry doesn't get consistent help on the offensive end, which puts a lot of the weight on her shoulders.

And yet the most impressive thing might be McCoughtry's increased willingness to pass this season: although she's knocked for turnovers occasionally, her p ass percentage of 49.6% is actually an improvement. That she does all the scoring she does while also being able to pass the ball makes her an extremely strong candidate right now though this race might come down to the last day this season.

Who's your choice for MVP? Let us know in the comments or write up a fanpost to make a case for a player not discussed here to share with the community.