Depending upon the specific laws of any given state board of medicine, the PA must have a formal relationship on file with a collaborative physician. The collaborating physician must also be licensed in the state in which the PA is working, although he or she may physically be located elsewhere. Physician collaboration can be in person, by telecommunication systems or by other reliable means (for example, availability for consultation). In emergency departments the laws governing PA practice differ by state, generally allowing a broad scope of practice and limited direct supervision.