Saturday, April 18, 2009

Threat Diagrams

As anyone who was in the pub on Sunday will already be aware, dangers threaten us at every turn. But how much should we worry? For those of you without advanced statistical techniques, I devised the following diagramatical method, illustrating on the left two threats discussed that evening, and on the right three threats to Jim's flat.

As we can see there are two axes, Likeliehood (sic), representing how likely the event is and Threat, representing how catastrophic it is. So on the left we have "Girlfriend biting head off during sex" as really quite unlikely[1] but extremely dangerous, while "Drunk man at bar asking for a joke" was very likely[2], but hardly dangerous at all[3].

What we might notice is that the area under each graph is approximately equal[4] and as this area is equal to likelihood multiplied by danger, I call this the threat level. Therefore if we are concerned about one of these dangers and take precautions, logically we should take equivalent precautions for the other. So if after this you are concerned enough after last weekend to look up a joke, you should also wear some kind of armoured helmet whilst in bed.

Similarly, on the right is the diagram for three threats I have identified for Jim's flat. Frogs have invaded the flat twice, making this quite likely to occur, but caused almost no damage. Despite this Jim has often time told me to shut the door to stop letting frog in.

Pterosaurs are unlikely to attack Jim's flat, as they are extinct[5]. As it is a basement flat with three flats above, even if they have survived extinction to attack East Kent, they will be unlikely to damage his flat, at least until they have dealt with his upstairs neighbours. This should allow Jim enough time to 1. update his threat chart and; 2. Acquire a harpoon gun.

Finally Molemen. This is molemen as in half-man half-mole digging monsters as opposed to any other molemen you may have heard of. These are fictional, although widespread throughout fiction especially comics, so the likelihood of an attack is low. The danger however is immense, having an equal threat area to frogs.

What I think surprised people in the pub, was not so much that I was comparing these threats, but that I was sketching the diagrams while doing so. What can I say? I'm just naturally gifted.

A similar way of looking at threats is put forward in this post by The Medium Lobster of Fafblog.

[1] Obviously if one were, for example, a preying mantis, the likelihood would have to be revised.
[2] He'd asked all of us, and frankly we mostly had pathetic jokes. I didn't resort to the joke about the man with 5 willies.
[3] To us anyway; his mockery of my height and a friend's name caused his personal danger level to rise by a small but measurable amount.
[4] However I skipped a few steps in the data collection, so this may not be accurate.
[5] One of the sites I looked at briefly whilst researching this post asked the question "Did pterosaurs survive extinction?" From first principles I must answer "no"; if they are extinct they did not survive, and if they survived, they were not extinct.

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