--- In

APBR_analysis@yahoogroups.com, igor eduardo küpfer

<igorkupfer@r...> wrote:

> <snip>

>

> The following is a comparison of the two FTA coefficients (.4

vs .457), as

> shown by the differences between offensive possessions and defensive

> possessions,by season. The smaller coefficient outperforms the

larger

> exactly half the time, although with a larger standard error. The

difference

> is small enough (to me) as to not warrant using the extra decimal

places.

> What is needed is some empirical data, counting actual possessions

in a

> game, and seeing how close we are.

I've got some of these. I'll try to pass them on after I'm done

traveling (again).

My general comment to Ben when he first passed on his note to me was

that he may be right that 0.45 works better to account for FT

possessions. However, there are minor errors in the rest of the

possession formula associated with team ORs and other little things

that get lumped into that multiplier on FTA. Or you can get more

complex with your possession formula, something BobC has done.

I share the sentiment that it doesn't matter too much. Soon, we will

be able to just count possessions for each team and do the simple

division to get pts/poss. Still, the formula estimate will remain

useful (in historical work, in individual possession calcs), but the

difference between 0.4 and 0.45 won't make a huge difference in

estimates. Plus, the multiplier changes with rules and enforcement

of such. It was lower in the 3-to-make-2 era, for example, and is

higher in the 1-and-1 world of college hoops.

DeanO