Bob Butler – the first director of the National Institute on Aging – and I had decided to write a paper on this issue and try to encourage people to conduct more autopsies, which is probably a losing proposition. Unfortunately, Dr Butler died about six or eight months ago, at a very young age – a tragic event in the lives of most of us in the field – so we never did get to write this article. And he had information, as a physician, that I, as a Ph.D., did not have, so I don't know that that issue is going to be pursued, but it's very important for people to understand that the causes of death in old age are rarely established with absolute certainty. In fact, I did write an article on this, in which I found that there were only two or three situations in the world where researchers – in Israel, the United States, and I think the United Kingdom – had assembled some small number, 25 or 50, autopsies of older people, for their own research purposes. They had funds to do it, because one of the reasons people don't do autopsies is because it's costly. No family member would probably want to do it just to satisfy some research curiosity, and hospitals surely don't want to pay for those... for that kind of examination, just to learn what caused death, when they're economically stressed already. In any case, the studies that I'm referring to, that did occur with small numbers of people, revealed something that was probably not unexpected. A bit less than half of the populations that they looked at, who were autopsied, died from causes other than what was reported on their death certificates. Now that's significant, because an enormous number of public health policies that are made by decision-makers are based on what is believed to be very accurate causes of death, at every age. If you're making a rule, or a law, or a public health regulation based on the causes of death in older people, with a 50% error rate, you've got a problem.