Disc is a behavioral model which is formed with the basis on Dr William Moulton Marstons work to examine people's behavior in their usual environment or within a specific situation. Disc stands for drive, influence, steadfastness and compliance. These are the four groups of human behavior that can help predict the action of that person within a given environment. This data is then kept in a profile to help the company develop a good understanding of the employee's personality. More here.