## Re: Tendex rating

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• ... stuff? ;) But ... Hey, going to Caltech means I know the formulas, how to derive them from first principles, what all the little math symbols mean, and
Message 1 of 6 , Nov 3, 2001
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>
> Hey didn't you go to Caltech and shouldn't you know this
stuff? ;) But
> you did nail the correct answer to the ellipse modeller: Kepler.
>

Hey, going to Caltech means I know the formulas, how to derive them
from first principles, what all the little math symbols mean, and how
to go 40 hours without sleeping. It doesn't mean I know the names of
the famous dead guys. Heck, by going to Caltech, I have a right to
forget names.

>
of
> good defensive players will STILL get arguments -- from people who
> complain that the list left out players X, Y, and Z, who are great
> defenders.
>
> It's analogous to statistics: you can be "conservative" and
minimize the
> probability of a Type I error by choosing a small significance
level. But
> in doing so, you are automatically raising the probability of a
Type II
> error.
>

This is pretty much my point. In policy making, a policy maker
really wants to reduce one of those types of errors. Usually the
policy makers don't care about the cost-benefit of Type I vs. Type II
errors. Their job is minimize one type and fight with everyone else
who wants to minimize the other type.

Not sure how that relates to any hoops stuff we're doing right now,
but it might in the future, when we start using all those funky math
symbols.

> Well there's another kind of consistency, one which is a good thing
to
> have: logical self-consistency. E.g. rating systems should avoid
> double-counting (unless there is a reason to put a heavy weight on
that
> variable).

That's true and a good . I can add that to the routine speech I give
at work. Then when my people look at me funny, I can blame it on you.

I would phrase what you're talking about a little differently here,
though. A method makes assumptions at the start and those
assumptions should remain true at the end. Thinking off the top of
my head -- if Tendex assumes all those things to be worth one point,
shouldn't they all be worth one point at the end, too? Does this
mean Tendex should add up to points scored?

I know all the arguments pro and con with Tendex. I always point out
that Tendex, when applied to teams has only about a 70-80%
correlation with winning percentage. Which means it's not terribly
reliable for predicting winning teams and probably no more reliable
for predicting winning players. I also don't like the fact that it
really just encourages a lot of shooting. I don't know how well
Tendex correlates with points scored. But unlike baseball, where
position players are pretty much responsible for offense and pitchers
for defense, basketball players are responsible for both. That's why
I try to keep offensive and defensive contributions separate for
individuals. Doug Steele has an offensive and defensive Tendex
rating based on some conversations we had in '94. It was a start.

DeanO
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