TimeTrex Time and Attendance

Would someone explain the difference between "Employee Groups" and "Departments"?
What is the purpose of Employee Groups?

Employee groups is just one more method to differentiate between employees. Since companies often have branches/departments that employees are in, using groups offers a third method to group employees by.

Some examples may be: hourly/salary, office/field workers, full-time/part-time/contract.

They are not required of course.