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Hello and welcome to The Spectators Book Club podcast.

I'm Sam Leith, the literary editor of The Spectator, and this week my guests are Professor

Daniel Kahneman and Professor Olivier Siboni, who are co-authors with Cass Sunstein of a new

book called Noise, A Floor in Human

Judgment. Welcome both of you. I'll start with a very, very obvious question, is what do you

mean by noise? Well, what we mean by noise is, first of all, judgment noise. Noise has many meanings. We refer to judgment noise,

and what we mean specifically is variability in judgments that should be identical. So it's when

the same person judges, makes the same judgment multiple times or different people who

should agree make judgments about the same object.

If they vary, that is noise.

It's like noise in measurement, and in general it's the easiest way to think about judgment, is to think about judgment as measurement

where the measuring instrument in the human mind. And then you have judgment noise is the equivalent

of measurement noise, which is a well-defined concept.

And what are some sort of examples? I mean, I think I know you start with the judicial

system as being a prime instance of a noisy system. Yes. I mean, it's a scandal, really,

at least in the United States. I don't want to speak for other countries, but in the United

States, a defendant facing a judge is really facing a lottery.

And the extent of the lottery is truly shocking.

Just to give you an example from research, if you take a defendant and a crime, the average sentence for which is seven years,

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