Week 1: The line starts here

First-come-first-served is not the natural state of a queue. It is a policy somebody chose.

22 February 2027

Almost everybody arrives at this course believing that a queue is simply what happens when a system runs out of capacity. That is not quite wrong, and it is a perfectly sensible place to start, but it does hide the interesting part. A queue is really what a system does instead of turning people away, and the shape it ends up taking is something that somebody, somewhere, actually chose.

We open with the thing that feels least like a choice at all. First-come-first-served looks for all the world like the absence of a rule, the default you end up with when nobody has decided anything. It really is not. It is a specific, defensible and quite unusual policy, and it has a history, and there are large parts of the world where it has never applied to anything that mattered.

Once you can see it as a policy you can see the others. By the end of the hour you will have four disciplines in your notebook and an uncomfortable question about which one your bank uses.

The argument#

1. A queue is a machine for handing out waiting.
2. The machine has settings. Order of service, number of servers, how much the waiting is allowed to cost.
3. Every setting is a decision about whose time counts for less.
4. Most of those decisions are invisible to the people they are made about, including the people making them.

That is the course. Everything from here is either the arithmetic that lets you see the settings, or the ethics of having chosen them.

What we do in the hour#

A queue you have all stood in, taken apart on the board. Where it starts, where it ends, who serves, in what order, and what happens when someone leaves. Then the same treatment applied to a transplant waiting list, which is the same object and does not feel like one.

After this lecture#

You can look at any queue and name four things about it: where it starts, who serves, in what order, and what happens to somebody who leaves. Nobody arrives at this course able to do that, and everybody leaves week 1 able to.

Before the field session#

Read nothing. Stand in a queue and time it, badly, with your phone. Bring the number and be ready to be told why it is wrong.