Role indicate the level or title of the person within the organization. Create a list of default roles in Settings > Roles.
Discipline indicates the type of work a person does within the organization, most often what department they’re in. Create a list of default disciplines in Settings > Disciplines.
Advantages of assigning roles and disciplines to people:
Allows you to set up bill rates for roles and disciplines that people can automatically adopt from your bill rate matrix.
Allows for detailed analysis per Role and Discipline in the Analytics section.
While individuals may have different roles or disciplines for projects, you can only assign one primary Role and Discipline per person.