One issue that comes up now and again is whether a player is likely to shoot more efficiently if he plays alongside other good players. Intuitively, the answer is "yes." If you need to carry the offense single-handedly, the defense can collapse around you and it's hard to score. If you play alongside other stars, by contrast, the defense is spread out and you can get easy shots. But just because it sounds reasonable doesn't make it true. Some evidence is suggested by the above chart of the Celtics new "Big Three," Kevin Garnett, Paul Pierce, and Ray Allen, all of whom shifted from being the clear focal point of an offense to forming one leg of a more evenly-balanced offensive stool.
As we can see, all three saw their shooting efficiency take a tumble last season and now they're doing better. Even more strikingly, all three are putting up career-high numbers in True Shooting Percentage thus far this season. That's not definitive proof that they're scoring more efficiently because they're scoring together but it's suggestive. Certainly it'll be interesting to see if that trend holds up over the course of the season. Another good case to look at would be Carmelo Anthony and Allen Iverson.