Most Americans spend far too much time worrying about things that are unlikely to happen to them, and ignoring things that put them at real risk. For instance, 600 people in the USA die each year by falling out of bed. No one worries much about that, but we all fear a bird flu epidemic, even though the disease hasn't killed a single US citizen (yet). Development of a vaccine against bird flu is high on the list of concerns, while readily available flu shots are ignored by many, although about 36,000 of us die from the common flu each year.

Jeffrey Kluger, writing in TIME magazine, pointed up our irrationality when it comes to risk assessment. For instance, mad cow disease could become a real risk if food safety regulators let their guard down, but no-one had died from it in the USA. Onthe other hand, our present eating habits contribute to the obesity epidemic that's responsible for thousands and thousands of early deaths annually.

And who hasn't felt that moment of fear when the plane hits a severe patch of high altitude turbulence? The risks of flying (though small) are far greater on landing or take-off, but high altitude lends an additional layer of anxiety: "If God wanted us to fly He'd have given us wings." As Kluger points out, much of the fear of flying is because we aren't actually flying the machine - the pilot is. If we were driving it (like our car), we'd be in control and we'd be much safer. We know we're better drivers than anyone else on the road, and that probably applies in the air as well.

Try to stop your teenager from smoking by pointing out the medical perils. It's a hard sell, largely because teenagers think they're immortal, and the immediate gratification wins out easily over the long-term outlook. The time factor is ignored.

It would be good if people would try to apply common sense in their assessments of risk, even though media reporting usually weighs heavily against it. Next time you feel the urge to campaign against a new nuclear power station, consider if you wouldn't be better occupied in protesting outside a tobacco company ...