

How Much Trouble is Early Foul Trouble?  - cwan
http://papers.ssrn.com/sol3/papers.cfm?abstract_id=1736633

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JoelSutherland
I just downloaded and took a look at the paper. I've got a problem with it --
it is only looking at data from 2006-2009.

This is an issue, because of the way that benching starters has become
conventional wisdom over the last 25 years. In fact, the foul out rate is down
over 40% during that period ([http://www.pistonpowered.com/2010/12/nba-
players-are-fouling...](http://www.pistonpowered.com/2010/12/nba-players-are-
fouling-out-less-often-and-other-interesting-facts-you-didnt-think-you-wanted-
to-know-about-fouling-out/)).

So on one hand, yes, playing a starter in foul trouble could cause them to be
less aggressive. On the other hand, I suspect there is VERY strong cultural
bias that magnifies this.

I would imagine that an NBA team that has either veteran players or a very
strong culture of understanding advanced statistics would be able to play as
well when in foul trouble. (Think San Antonio, Boston, Dallas and Houston). I
would also imagine that the evidence would not be as strong when looking at
other time periods.

So it's an interesting observation, but it makes sense that coaches approach
this issue on a case-by-case basis. Play Tim Duncan, bench Blake Griffin.

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alanpca
I've been hugely interested in doing some related interest in the sport of
Football. I've found that the official stats provider of the NFL, Stats Inc,
charges about $40,000 per year for API access to their stats.

Also, the paper reads like academic research, but the layout and citations
look rather simple. What gives?

EDIT: Their data source is listed, skimmed over it.

~~~
alanpca
I'd like to add the main author's page:

<http://philmaymin.com/home>

Looks like he has quite a bit of credentials and a huge interest in
basketball. Very impressive.

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kia
Abstract:

We use a large dataset of play-by-play NBA data to determine when yanking
foul-plagued starters is optimal by applying insights and tools from finance.
We find that a team performs significantly worse if a starter with foul
trouble is allowed to remain in the game, and that this effect is strongest in
the third quarter. We use a novel win-probability technique that is
sufficiently general to be useful for other questions simply by appropriately
redefining the state variables. Thus, our two contributions are to introduce
the new approach and also to demonstrate its usefulness by solving the problem
of early foul trouble that had remained unaddressed in the academic
literature.

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ams6110
Given the financial stakes at play in professional (and even amateur)
athletics, I find it hard to believe that an analysis of optimal "play or sit"
strategy wrt player fouls has "remained unaddressed" though a cursory search
on Google Scholar didn't turn up much of anything in the way of a counter-
example.

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jdminhbg
It's likely that an analysis has been done, but isn't public. Teams keep lots
of advanced stats to themselves as a competitive advantage.

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snowbird122
I didn't read this paper, but I never understood why players who get into foul
trouble are pulled from games. I guess the only explanation is that players
play differently after a few fouls. Otherwise, it doesn't make sense to take
someone out so that you don't have to take them out in the future.

~~~
matwood
Few basketball games are blowouts. The logic of sitting your best player(s) in
foul trouble is to hope that your bench can keep the game close so that your
best player can win the game in the end.

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akronim
Why not keep them out there and get a lead sooner, then hope to keep the lead
if they do foul out?

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detst
I think the idea is that having a lead early versus late gives the opposition
a more clear goal with the time to come back.

Basketball games and seasons are very long. Players won't be focused in the
entire season or for entire games. Having a deficit to come back from, with
the time to do it, gives them a clear objective to focus in on.

