How to calculate Offensive Rating for teams

[bblitics]

Hello to everyone,

i've tried to calculate Offensive rating using this formula:

Offensive Rating= Point scored * 100 / Possessions

where Possessions = .96*(FGA-ORb +TO+ (.44 * FTA))

Take for example this game, http://www.basketball-reference.com/box ... 70CHI.html

Using the formula above, the ORTg for Chicago is : 97,9845...

while ORTg for Cleveland is : 98,4856

but if we take a look on the basketball-reference site, the ORTg aren't egual. Why? Where am i wrong?

What is the formula they use?

Please help me.

Kind regards.

[Crow]

I don't recall if they use a slightly different formula for team possessions or use actual possessions calculated from play by play. It probably is one or other. I didn't see a team formula for offensive efficiency at their site. You can email them and ask, especially if nobody steps up with the answer here.

[feyki]

For teams, the formula is: 100 x Pts / 0.5 * ((Tm FGA + 0.4 * Tm FTA - 1.07 * (Tm ORB / (Tm ORB + Opp DRB)) * (Tm FGA - Tm FG) + Tm TOV) + (Opp FGA + 0.4 * Opp FTA - 1.07 * (Opp ORB / (Opp ORB + Tm DRB)) * (Opp FGA - Opp FG) + Opp TOV))

[bblitics]

I don't recall if they use a slightly different formula for team possessions or use actual possessions calculated from play by play. It probably is one or other. I didn't see a team formula for offensive efficiency at their site. You can email them and ask, especially if nobody steps up with the answer here.

For teams, the formula is: 100 x Pts / 0.5 * ((Tm FGA + 0.4 * Tm FTA - 1.07 * (Tm ORB / (Tm ORB + Opp DRB)) * (Tm FGA - Tm FG) + Tm TOV) + (Opp FGA + 0.4 * Opp FTA - 1.07 * (Opp ORB / (Opp ORB + Tm DRB)) * (Opp FGA - Opp FG) + Opp TOV))

Thank you to both, i've re-calculated using the formula above and the result now is correct.
Thank you guys.