The Tendex system is a basketball mathematical statistical formula that was created by sports writer Dave Heeren, in order to determine the playing efficiency of basketball players. It is generally accepted as the original weighted advanced stat formula used in the sport of basketball.

The Tendex statistical system has 3 different formulas and is calculated as follows:

Standard Tendex Rating: (Tendex raw statistical formula)

Modified Tendex Rating: (Tendex weighted average statistical formula)

European Tendex Rating (Performance Index Rating (PIR)): (EuroLeague / EuroCup)