22 Nov 2021

This is the metaphor I use to assess risks and prioritise the 'defensive' half of my work, in both the professional and personal spaces. Mostly it's a purely mental model, but I occasionally draw out the radar diagram. Things are less stressful when you can see them all.

It's not far off from the classic urgent/important task matrix, blended with the probability / impact risk model, and some dramatic imagery.

The Model

We're on a spaceship in an asteroid field. There are a lot of big rocks and some of them are heading for us. We have a radar that can see nearly all of them, and a laser that can vaporise some of them. We need to continually choose targets.


How fast is it moving? How long will it be until this either hits us, or passes by?


How likely is it that this will hit at all?


How big is it? How much damage will it do if it hits?


How efficiently would the laser work against this target?


Some, perhaps most, of these rocks are going to hit us. By acting intentionally, we get to choose which ones.

First in the triage are the ship-breakers - is there anything out there so big that we can't survive the hit? If so, we need a speed/angle assessment right now.

Very large, low-albedo, likely-angle rocks are the most important thing you're doing today.

Very large, high-albedo, very-unlikely-angle rocks are nightmares. There's nothing you can do anyway, so it's best not to think about them.

Large, slow rocks are the things you need to keep chipping away at whenever you get a moment. If you focus fire now, you'll get pasted by the faster ones in the meantime, but you don't want to let them get close.

Objects Are Further Away Than They Appear

It is usually, though not always, true that things are much larger and also much slower than you think they are: "The crisis takes a much longer time coming than you think, and then it happens much faster than you would have thought.” - Rudiger Dornbusch

Internalising this has made a big difference to my risk planning - you have longer than you think, but you'll get hit harder than you expected.


The metaphor breaks slightly for permanent, rather than time-bound risks; perhaps an orbiting comet?