In addition, a growing variety of centers (18-20%) are now run by medical facilities or physician groups, who utilize or hire their own center and administrative staffs or utilize existing supplier centers to serve the employee population. Lastly, an increasing variety of employers are getting involved in shared, multi-employer clinics, situated either on one company's area or centrally located.The supplier will develop, staff and manage the center either at the request of a group of companies or will get employers in a specified geographical area. No matter the design used, it's essential that company remain engaged in supplier selection, center oversight, tactical and policy instructions. Staffing practices vary from one onsite clinic to another, though over 60% of centers are led by a Nurse Professional or Doctor's Assistant.