The player isn't necessarily doing nothing. His team scores 1.08 points per possession (the result of adding up those percentages). But we don't know what any individual player, including the one we're evaluating, is doing. And that's the whole point. You can't tell from plus-minus what contribution any one player is making to the team. Sure, you can use it to decide that Gary Clark is better than Nsoseme. But it's not really useful when trying to distinguish between players like Jenifer and Broome.looking at his experiment he had the guy out there do nothing while everybody else on the court had 3% chance of scoring 1 point, 30% chance at 2 points, 15% chance of 3 points. i dont know if thats the best experiment to run, clearly those numbers are going to go crazy running simulations.
I think better arguments against Jenifer are that he has a very low usage rate, his true shooting percentage is under 50%, and he doesn't rebound or draw fouls. His defense needs to be elite to make up for that.