The connection between usage and offensive efficiency has been firmly established for quite awhile, although it's exact numeric dimensions depend on the player and situation. The language I'm using may be unfamiliar, but I assure you the idea is not. Take the case of Tyson Chandler, the current league leader in both FG% and Individual Offensive Rating. Chandler's incredible offensive efficiency is possible, in part, because he only uses 14.2% of the Knicks' offensive possessions when he's on the floor. If the Knicks' offense needed Chandler to use more possessions, he would have to produce in new and unfamiliar ways, making him less efficient. Essentially as his usage went up his efficiency would inevitably decline.
This works in the other direction as well. Imagine how efficient Kevin Durant could be if the Thunder had enough other offensive talent to allow him to take just 10-12 shots a game. He could pick and choose the most valuable shots and his efficiency would go through the roof. For a less hypothetical example, take a look at Kevin Martin. Since joining the Thunder, Martin his seen his Usage Rate cut from 24.7 to 21.2. His Individual Offensive Rating has jumped from 111 to 122.
The Pacers have been struggling with this trade-off all season long. Granger's possessions have essentially been divided up among the rest of the team, bumping up the Usage Rate for most players and dragging down efficiency. To illustrate this phenomenon I put together the Google Motion chart below. The chart graphs each current Pacer by their Usage and Individual Offensive Rating from last season. The color of each mark is a measure of the player's minutes per game. If you scroll over any of the marks you can see which player it represents and their stats. The real story of the chart is told when you press the play button. Each mark will then migrate from that player's 2012 statistics to what they've done this season.
Five players have decreased their Usage Rates this season - Gerald Green, D.J. Augustin, Sam Young, Lance Stephenson and Tyler Hansbrough. There probably isn't a ton to be gleaned from Young's change, he played sporadically last year and should be this year as well. Green and Augustin have both used far less possessions this season, not a surprise given that they have transitioned from starting to supporting roles off the bench. What's amazing is how far the offensive efficiency has fallen for both players. Normally a drop in Usage connects with an increase in efficiency but the swirling mess of ineffective offense around them has dragged their numbers down to.
The other two players to decrease their usage, Hansbrough and Stephenson, are the only two players on the team who have increased or maintained their Individual Offensive Ratings this season. Obviously Stephenson has taken a developmental leap, but Hansbrough seems to have settled into a nice usage niche. His field goal percentage is still frustratingly low, but his offensive rebounding his taken a significant jump and he's averaging 9.2 FTA per 36 minutes. The best offensive play Hansbrough can make is usually a trip to the free throw line and 29.7% of his offensive possessions have ended that way this season, up from 18.3% last season.
The four players who have significantly increased their Usage Rates, soaking up Granger's possessions, have all seen their Individual Offensive Ratings decrease, in some cases significantly. Ian Mahinmi's has dropped by 22 points per 100 possessions and Paul George's has dropped by 13. George Hill and David West, have carried the Pacers' offense for huge stretches this season, but the offensive efficiency of both has suffered for the sake of these larger roles. West's Individual Offensive Rating has dropped by 1 point per 100 possessions, and Hill's has dropped by 6. It's terrifying to imagine what the Pacers' season might look like at this point if their efficiency had fallen any further.
Roy Hibbert is easily the most frustrating case on this chart. His Usage Rate has essentially stayed the same but his Individual Offensive Rating his dropped by 19 points per 100 possessions. What's happened to his game has nothing to do with a trade-off between Usage and efficiency, it's is just a pure unadulterated slump.
Until Granger returns there aren't many realistic scenarios for dividing offensive possessions differently. The good news for the Pacers' is that the efficiency declines of Hibbert and George are so drastic, that they appear completely out of whack with what would be expected. That means that bulk of their struggles probably have less to do with an increase in offensive responsibilities and more to do with the nature of their responsibilities. Although it offers precious little solace at this point, their problems have solutions as opposed to being the manifestation of an absolute statistical truth. Whether or not the Pacers' can find a way to help Hibbert and George be more efficient in the current roles is another matter entirely.