Week 7: The queues with no visible front

A visible line is a courtesy. The queues that decide the most about a life publish nothing.

19 April 2027

This one is a guest lecture, and it is the hinge of the semester.

Everything up to the break has been a queue you could actually see. You could count it, stand in it and time it, and it is easy to assume that is normal. That property turns out to be quite unusual. Visa applications, social housing registers, court lists, insurance claims, specialist referrals and complaints to an ombudsman are all queues, and almost none of them will tell you your position, the length of the line, or the rate at which it moves.

Marta Ilves spent eleven years processing applications and four more investigating the offices that process them. She is here to describe what happens to a queue when nobody outside can measure it, and what happens to the people inside it who can.

What the invisibility does#

• You cannot balk. Leaving a queue you cannot see the length of is a decision made without information, so people stay in queues that will never serve them.
• You cannot plan. A wait of unknown length is not a wait, it is an open question, and week 8 is about what that costs a person.
• You cannot complain about your position, only about the whole system, and systems absorb that easily.
• Last-come-first-served creeps in. Without an audited order, the file on top of the pile is served first, and the file on top is the one that was touched most recently.

What it does to the office#

This is the half of the lecture that surprises people. An office whose backlog is invisible to the public is usually an office whose backlog is poorly visible to itself, so the staff turn out to have their own version of the problem.

Measuring anyway#

There are three techniques for putting a number on a queue that publishes nothing. You can file freedom of information requests, you can track a cohort from the outside, and you can follow the timestamp trail a system leaves whether it means to or not.

After this lecture#

You can estimate the length of a queue that refuses to tell you.