Consider the arrival of patients into a public health clinic. Some patients are ill; some are injured; some are elderly; and some are very young. Some cases may be life-threatening, while others are inconsequential. How do the basic dispatch rules fall short in this situation? Design a dispatch rule for scheduling these patients.

First come, first served is inappropriate because it ignores the urgency of treating the most serious cases. There is no "due date" on which to base lateness or critical ratio sequences. Most students will write a "priority" rule that behaves like triage-assigning an urgency code to each patient, and taking highest urgency cases first. Student rules may have more than one part; for example, patients may be sorted by urgency code, and by treatment time within urgency code. They may also create a separate code for contagious cases.