Quotulatiousness

August 5, 2018

QotD: Risk aversion

Filed under: Economics, Quotations — Tags: , , — Nicholas @ 01:00

… let’s step back and ask ourselves what insurance is for. Classical economics has an answer: people are risk-averse, which means that they will pay good money to reduce the variability of outcomes they face. If home insurance guards against the loss of a million pounds when my house burns down, I’m happy to buy the insurance even though the insurance company expects to make a profit from it.

But this risk aversion emerges from the fact that money is worth more to poor people than to rich people. Gaining a million pounds would make me rich but losing a million pounds would make me poor. I should not gamble a million pounds on the toss of a coin, because the million pounds I might lose is more precious to me than the million pounds I might gain.

As so often with classical economics, this is an excellent description of how we should behave. It is not such an excellent description of how we actually do behave. Risk aversion can only explain why we insure large risks. It cannot explain why we insure small ones. This is because risk aversion turns on the idea that an extra pound is worth more if you are poor than if you are rich. But having to replace a phone is not going to make the difference between poverty and wealth.

In one of my favourite economics articles, written in 2001, the behavioural economists Richard Thaler and Matthew Rabin point out that anyone who rejects a 50/50 gamble to win £10.10 or lose £10 — apparently a reasonable enough taste for caution — cannot possibly be doing so because of risk aversion. (The degree of risk aversion necessary would mean that the same individual wouldn’t risk £1,000 on the toss of a coin for all the money in the world.) Risk aversion simply cannot explain why anyone would turn down that fractionally favourable gamble. And it cannot explain why anyone would insure a mobile phone.

A better explanation is that we tend to view risks in isolation. Rather than telling ourselves “a lost mobile phone would lower my lifetime wealth by 0.005 per cent”, we tell ourselves “it would be so annoying to have to pay for a new mobile phone”. Isolating and obsessing about risks in this way is arbitrary and illogical. But that does not mean we don’t do it.

Tim Harford, “How insurers keep the money-pump flowing”, TimHarford.com, 2016-09-21.

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