Re: PPS vs. FG%

[Francis Hsu <francis@ai.mit.edu>]

On Thu, Oct 18, 2001 at 04:15:35PM -0400, Berry, Mark  S wrote:
> Good question Francis. For me, there are a couple of reasons. First, I have
> a better understanding of the context of field goal percentage. That is, I
> know 41 percent stinks. I really couldn't tell you, without doing a little
> research, what a good points per shot is. Probably not a good reason, but
> that's one.

Points per shot is points scored / field goal attempts.  The reason why I
like it is because it takes free throw points into account.  Warwick's
example of Eric Williams is a good one.  If you used FG % to measure his
offensive efficiency, he looks like one of the worst on the Celtics.  But
if you used PPS, he's better than Walker.

> Also, I think points per shot is deceiving. It's easy to say "take 90
> three-pointers and make 33 percent, and that's the same as taking 90
> two-pointers and making 50 percent." In the strictest sense, that's true.
> But that's 15 more missed shots, which leads to 15 more fast-break
> opportunities for the opponent. Never mind the damage quick three-pointers

Thanks for pointing that out.  I hadn't thought about that, although I
guess I am strictly looking at offense, regardless of the impact it has
on defense.  Perhaps you are right, that PPS puts too much of a premium
on 3 pointers.  But, at the same time, FG % ignores free throws, which
makes it just as bad to me, if not worse.  FG % also gives 2ptrs the same
value as 3ptrs.  Would you rather have someone who makes 50% of their 3's
or 50% of their 2's?

> returns the more you shoot the three-pointer. Now, I'm oversimplifying,
> because I'd guess points per shot also calculates free throws (doesn't it?),
> but you get the point. As an example of that last point, I'm betting Iverson
> and Stackhouse, who shot comparable FG percentages to Antoine last year,
> probably score more points per shot because they were among the league
> leaders in FT attempts and makes, while Antoine was nowhere near the leaders
> in that category. Of course, if FTs aren't figured into the equation, I'm
> way off base.

I'm sure that Iverson and Stackhouse have a better PPS than Walker.  If
anything, using PPS makes Walker look worse than Iverson/Stackhouse than
going by FG %.  Which is why I lean towards looking at PPS over FG %.

> Neither one is perfect, but I think FG percentage does a pretty good job of
> measuring offensive efficiency, especially when considered along with FT
> attempts and makes.

Using your fast break example as a reason in favor of deemphasizing the value
of 3ptrs, would you then consider free throw points to be the most valuable
of all, since free throws would prevent fast break opportunities even more
than taking 2ptrs?

Francis