APBRmetrics

Synergy ranks the Bulls offense as the 14th best Offense in the league at .91PPP

According to BBR, the Bulls have an Offensive RTG of 107.4, good for 5th best.

What am I missing?

Im guessing it has something to do with Offensive Rebounding but Im not smart enough to figure it out. Would anyone care to lend me a hand?

The word "possession" means different things in the two places. At b-r (and for most (if not all)) of us here, a possession starts when one team gets the ball and ends when the other team gets it back. A possession can include multiple "plays" -- such as a missed shot and an offensive rebound. At Synergy, a new possession is created when there's a missed shot or a foul that doesn't involve a change in which team controls the ball.

Essentially, Synergy possessions could be estimated with something like FGA + .44 x FTA + TOV

B-R's possessions could be estimated with something like: FGA + .44 x FTA - ORB + TOV

Synergy does not estimate anything, they are counting plays. PPP on Synergy means "points per play", not per possession. The offensive rating is points per 100 possessions. The Bulls have more plays per possession, because their offensive rebounding gives them more opportunities for plays. But an offensive rebound keeps the possessions of the ball. Points per possession or offensive rating is more meaningful than ppp.

The Bulls are the clear leader on team OR% and so that moves their points per possession further above their points per play than for anyone else.