Paul Millsap better have a heck of a year

Sequels almost never live up to the original, but The Empire Strikes Back, Dr. No, and High School Musical 2 just got company: Tom Ziller is back at Ballhype with "Love and Mathematics, Pt. 2," and it's a doozy. The post is notable not for what it proves but what it disproves: The fallacy that more minutes equals decreased production.

With data support from Ballhype founder Jason Gurney, Ziller goes deeper on what he calls "The Paul Millsap quandry," in honor of the Utah Jazz rookie (the theoretical test case we keep returning to) who put up sterling production in about 18 mpg last year.

But would Millsap be just as good a starter as he was a sub? Or would playing more minutes against first-team competition expose his weaknesses? It's that sort of question that's been floating around since Plissken at the Buzzer first questioned PER, John Hollinger's kitchen-sink stat on NBA players' offensive performance, over the weekend. (See recap here). FreeDarko's Silverbird5000 and Bethlehem Shoals then advanced the debate by discussing how the inequalities of NBA play muck up the data in a way that makes Hollinger-style statistical analysis misleading.

However, Ziller limits himself to a data set (251 role players whose role increased the subsequent year) that made sense to this blogger. To summarize his analysis, 70% of the players incurred a slight-to-significant increase in production, while 28% of the players declined. Citing the standby correlation vs. causation rule, Ziller's cautious about the significance of these findings:
I want to emphasize this again: We don't know [whether Millsap's per-minute production would suffer, improve or be maintained given more playing time]. We cannot look at any of this data and say "Increased minutes leads to increased per-minute production (aka efficiency)" just as we cannot and should not say "Increased minutes leads to decreased per-minute production." But this data does indicate a positive relationship between minutes and efficiency.
(In this corner, I'm guessing that more playing time tends to correlate with an NBA player's progression, having always thought of mpg as somewhat of a bell curve. Thus, players are getting better as they earn more minutes. But you know what...I'm more than happy to let Ziller, Jason, and co. do the math on that).

Still, Ziller hammers home a key insight: That more playing time doesn't mean a player's PER will necessarily go down. And yes, this conclusion may be intuitive to some of us, but given the fray that's gone on the past few days, sometimes it takes a big stick of data to truly get the attention of non-believers.

Whew! When does Professor Dean Oliver stroll into town?

Now, to you--the reader who stumbled across this.

Look, I'm not going to kid you--I'm glad you're reading this, but this debate is moving well out of the scope of We Rite Goode at this point. We can follow the argument and will continue to happily dumb it down summarize it, but Ziller, the Darko guys, and the Plissken gang all write just as goode (and include snazzy graphics) in their increasingly detailed arguments. If data is your scene, head yonder to get your learn on.

However, if you want to read about mediocre athletes and cheese, and usually not in that order, stick with us.

Note: There are some who point out--and perhaps rightfully so--that a conversation so focused on PER leaves out the other school of thought on basketball statistics put forth by Dave Berri. I can't speak for the model--as it's been nearly a year since I looked at Wages of Wins, and remember only that I found it lacking--but FreeDarko was clinically dismissive of the work.

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posted by Doctor Dribbles @ 00:27,


At September 12, 2007 at 10:51 AM, Anonymous TZ said...

I'd be happy to address Berri's work if he laid out how he arrives at his results. I mean, we know how to calculate PER, a proprietary stat which is owned by an ESPN analyst. Yet we have no real idea how to calculate Win Score, which is a proprietary stat owned by an academic from a state college in Bakersfield, Calif.

< / grumbling>

At September 12, 2007 at 11:58 AM, Blogger Jarrett Carter said...

If Charles Barkley says he will be a beast, then I'll believe it.

At September 12, 2007 at 12:49 PM, Anonymous Anonymous said...

ziller's argument isn't as strong as you make it out to be. 30% of the players saw some decline with more playing time--that's a pretty substantial minority, in my mind.

At September 12, 2007 at 1:28 PM, Anonymous Anonymous said...

If you want to know what the real minds in basketball statistical analysis (the dozen or so guys who work for teams) think of this debate go over to and ask them

At September 12, 2007 at 1:46 PM, Blogger Hot Shit College Student said...

I've seen more than few re: Berri comments snuck in at places where this bore-a-thon has been covered. TZ is right, WoW's secret formula is a big turn off. Berri's rips on PER around a year ago seemed like nothing more than an attempt at getting some attention. He didn't have to attach himself to that unconvincing refs-r-racist study either.

At September 12, 2007 at 6:54 PM, Blogger Doctor Dribbles said...

TZ and HSCS, I'm feeling better for dismissing Berri knowing that you two basically do the same (albeit, in very different ways).

Anon, did you read the Ziller post in full? The decline for players w/more PT is actually pretty negligible compared to those who improved, among other rejoinders.


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