Having seen some of Dr Spiegelhalter's talks in person, he most certainly knows that the units are not based on a meaningful operation. He is extremely passion

Having seen some of Dr Spiegelhalter's talks in person, he most certainly knows that the units are not based on a meaningful operation. He is extremely passionate about explaining uncertainty and risk to ordinary people. As an example, plenty of people think that "you either get cancer or not, so it's 50-50, and might as well leave it to chance". In other cases, politicians ask scientists for the "worst possible outcome" of an event, and then react as if it was a certainty or at least 10% probability, while in reality the risk might be extremely small. Most people have trouble with the very concept of uncertainty. Microlives, and their opposite, micromorts (1-in-1M chance of dying while doing something) are helpful in comparing improbable-but-terrible events in terms of certain-but-insignificant, easier to understand concepts.