A clinician is a health care professional that works as a primary care giver of a patient in a hospital, skilled nursing facility, clinic, or patient's home. A clinician diagnoses and treats patients. For example, physicians, nurses, nurse practitioners, and physician assistants are clinicians; a speech-language pathologist (SLP) is a clinician, a speech-language pathology assistant (SLPA) is not. Clinicians take comprehensive exams to be licensed and some complete graduate degrees (master's or doctorates) in their field of expertise. Although a clinician must follow evidence-based best-practices and other professional codes of conduct set by laws and professional governing bodies, a clinician can choose to practice without another's supervision.