Week 6: Triage

Emergency medicine solved the ethics of priority in public and wrote the answer down. It is worth reading.

29 March 2027

This is the last week before the break, and it is the week I care most about.

Week 5 will have left you with priority as a mechanism, and most likely with a slightly queasy feeling about who gets to set the classes in the first place. This week is about the one field that had to face that question head on, could not avoid it, and produced a public, documented, argued-over answer. Emergency triage is the most examined queue discipline in existence and almost nobody outside medicine has read it.

A triage scale is a priority queue where the cost of being in the wrong class is measured in lives. It is also, unlike almost every other priority system you will meet this semester, written down, taught, audited and revised. That combination is rare enough to be worth a lecture on its own.

What a triage category actually is#

We work through a five-category scale of the kind used in Australian emergency departments. Note what the right-hand column is. It is not a description or a priority number, it is a promise in minutes, published, and audited against.

We work through what each category promises, what evidence that promise was set from, how it is audited afterwards, and what happens to the categories once the department comes under load.

Then we reach the part that never makes it into the summary. Triage does not rank people by how sick they are. It ranks them by how much the waiting will cost them, which is a different and much stranger quantity, and it is why a person in agony can correctly be seen after somebody who looks fine.

Where it breaks#

• Under sustained overload, triage stops being a queue discipline and becomes rationing, and the scale was not designed for that.
• The categories encode assumptions about who presents and how, and those assumptions are not uniform across a population.
• Undertriage and overtriage have very different costs and the same audit.

The transferable part#

You are not going to build a triage scale. What transfers is the demand triage makes and almost nothing else does. Say what your categories promise, in units, in public, and then measure whether you kept it.

Hold that against the next queue that quietly sorts you.

After this lecture#

You can read a published service standard and say what it promises, in units, to whom, and how anybody would know if it were broken. That is a rarer skill than it sounds and it is the one the essay in week 8 is marked on.

After the break#

Week 7 is the opposite case, and Marta Ilves comes in to take it. Her subject is the queues that publish nothing at all.