Timeline of EverythingDisc
1994 - 28-box Personal Profile System
A research effort was launched to improve the DiSC instrument that had basically remained unchanged since 1959. New items were added, non-functioning items were removed, and the overall reliability of the instrument increased. The new PPS was named the Personal Profile System 2800 Series (PPS 2800), referring to the new number of tetrads (28). First published in 1994, this version of the PPS is still used today, although it has since been renamed DiSC Classic.