Saturday, September 10, 2005

Offense and Defense

I have been in a lot of discussions about the defensive drop in the Storm this year so I decided to run some of Dean Oliver's formula against the past four years of team statistics for the Storm. I want to dive into the individual player statistics next, but, frankly...I'm not that far along in the book yet, and the formulas get very complicated when reviewing individual player defense, which is what I am really interested in. I can tell what happens to the team...but I'd like to see where the change actually occurs.

As a review, I am using the possessions calculation formula that looks like this...

Possessions = FGA - OREB/(OREB+DDREB) * (FGA-FGM) * 1.07 + TOV + 0.4 * FTA

DDREB refers to the defensive rebounds grabbed by the opposing team.

Once I determine the number of possessions for the Storm and their opponents for the season, I average the two together and then use that to determine the number of points per possession and the number of points allowed per possession. Finally I multiply those by 100 possessions to determine Offensive Rating and Defensive Rating numbers.

Here is how they come out...(updated 9/12 to reflect formula errors)

Offensive RatingDefensive RatingDifferential

So what does this say to us? The first surprise to me is that the offense actually dropped this year. The second is how strong the differential was back in 2002, which was Lin Dunn's last year and the first year the Storm made the playoffs. Obviously the strong defense last year separated the championship team from the rest of the teams. That differential has been the biggest factor in the championship and determined the finals winner in almost every season of the leagues history. I believe there may have been one year where the #2 team differential wise won.

The difference in the defensive rating between 2005 and 2003 is fairly small, meaning there must be some key piece unique to 2004. Strangely enough, Sheri Sam is the only person unique to 2004. Burse and Lennox stayed in 2005, and Tully and Kamila were there in 2003. That said, either Sheri was a much more important defensive element than anyone understood, another player rose or fell enough defensively to swing the numbers, or a number of players moved up or down enough together to swing the numbers. (The difference is not so small after all now that the formula is changed. 2005 has the worst defensive rating for the Storm in the past 4 years.)

This is where the individual defensive ratings would be interesting to look at. I guess that I have some reading and some numbers crunching to get cracking on.

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