It is possible to add HR Specialist to any of the departments and HR Specialist doesn't have to work in the department where she/he has the HR Specialist permissions. HR Specialist permissions provide an opportunity for HR work within the specific deparment and its subdepartments - manage the evaluation and appraisal interview questionnaire templates, manage the department (and subdepartments) structure and start and manage evaluations and appraisal interviews.
Similar to the HR Manager, HR Specialist can't see the information about his/her own and his/her manager's evaluations and appraisal interviews.
The difference between HR Manager and HR Specialist permissions is that HR Specialist is able to see only the specific department and its subdeparments, while HR Manager can see the whole organisation. HR Specialist can't start or manage satisfaction surveys.
You must go to the department profile to add HR Specialist.