How does a per diem position work?

The way a per diem position works varies a little from one job to the next. Generally, hospitals and care facilities rely on per diem nurses to fill holes in the schedule. In some institutions, per diem employees are called when needed. In others, there are many hours available each week, and they are doled out based on seniority or a first come first served basis; they may also just be assigned by a supervisor based on the availability reported by the nurse ahead of time. The hours usually vary from week to week. Many hospitals use agencies to find per diem nurses.