We had an employee abruptly leave our finance department and in doing so increased duties were passed on to the remaining four staff members. The supervisor has told them that these additional duties will remain in place indefinetely. Out of the four staff memebrs, one employee "Mark", who had questionable performance before the increased responsibilities, is stating that the workload is too much and unfair. This employee can be seen leisurely walking the halls, stopping and talking to other staff about non-work related issues, taking personal calls from their cell phone daily, hanging out in the breakroom and taking leave time every single week for one thing or another be it he has a doctor appointment or he is not feeling well. I want to know how can we fairly measure productivity? How do we know that what the supervisor is asking is not too much or how do we know that what the employee is producing is not enough? Any help is appreciated. Thank you.