Wheelchair basketball classification is based on the players' functional capacity to complete the skills necessary to play - pushing, pivoting, shooting, rebounding, dribbling, passing and catching. It is not an assessment of a player's level of skill, merely their functional capacity to complete the task.

In particular, the trunk movement and stability observed during these actual basketball situations, forms the basis for the assignment of a player to a particular class.

Players are assigned points as their classification - 1, 2, 3, and 4 are the recognized classes, with 0.5 classes between for the exceptional cases which do not fit exactly into one class, and the 4.5 category for the player with least or minimal disability.

Classes are defined according to players' "volume of action". Each class has a clearly defined maximal volume of action, which the player may exhibit. The volume of action refers to the extremes to which a player's trunk stability will allow them to reach, without holding on to the wheelchair, before overbalancing.