I don't know exactly what is in his adjusted +- stat, but +- in general is pretty team dependent.
Even by his own numbers he is really just saying Pierce was better for longer, but Wade had a higher peak. Also a very good chance that number is skewed by Pierce playing on better teams far longer into his 30's than Wade did.Since when does playing on good teams helps ones individual stats?
It is the exact opposite.
Just a few examples:
Booker would play 17 mins and average 8 points here. Not 35 and 27.
M. Jordan had his best statistical years when he didn't win.
Manu was the 3rd best guard of his generation, he averaged 15. Elsewhere (when he wasn't in SAS) he got 26.
Pierce averaged better numbers when we were tanking.
RW got his TD's when Thunder stopped to exist as a contender.
It's basically another name for ESPN's Real plus minus
Since we know Danny's looking at it here are some Celtics' rankings from this year in real plus/minus:
Kyrie Irving: 17th overall, 6th among point guards
Al Horford: 21st overall, 6th among centers
Marcus Smart: 38th overall, 12th among point guards
Jason Tatum: 85th overall, 14th among small forwards
Gordon Hayward: 126th overall, 24th among small forwards