This is a statistic designed by Dr. Dean Oliver, author of the seminal work on advanced basketball statistics, "Basketball on Paper." This particular statistic measures how many points a player produces and takes into consideration their made shots, assists, and offensive rebounds.
There are different weights assigned to different scenarios. For example, a player who assists on a two point field goal receives 25% of the scoring possession, which is about 0.5 points produced. A player who assists in a three-point field goal gets about 15% of the scoring possession, which again works out to about 0.5 points. In those scenarios, the player making the basket gets the majority of the credit (as they should), getting 75% and 85% of the scoring possession credit respectively. This statistic is helpful for determining how much a player helps the offense. Every coach knows a made shot is not just one player making a shot, but his/her whole team contributing. This statistic helps measure teamwork.