Who can provide a peer reference for licensed practitioners such as nurse practitioners, physician assistants, and psychologists, midwives, and social workers when there is no other similar practitioner on staff?  

The definition of a peer is someone from the same discipline. For example, physicians for physicians, dentists for dentists, podiatrists for podiatrists, etc. It does not have to be someone in the same specialty (orthopedist, etc.). To be able to provide a reference, the peer must be familiar with the individual's actual performance.  For the nurse practitioner, physician assistant, and psychologist, or social worker, the peer should ideally be another individual from the same discipline and the organization should attempt to obtain such references. This could be someone within the same organization or someone from outside the organization.

In situations where there is no nurse practitioner, physician assistant, psychologist, or social worker who could provide a peer reference it is acceptable for a physician with essentially equal qualifications, and who is familiar with the allied health practitioner's performance, to provide the reference. For example, an internist could provide a reference for a physician assistant, an anesthesiologist could provide a reference for a nurse anesthetist, a psychiatrist could provide a reference for a psychologist, and a psychologist with similar responsibilities could provide a reference for a social worker.