Wired notes the challenges inherent in any present study of a potential life-extending therapy in humans: "Longevity is one of the hottest areas of science, but there's a curious hole in the research: Scientifically speaking, nobody knows how to measure aging, much less predict reliably how people will respond to time's ravages. ... Unlike models of drug development for the diseases of aging, which have consensus endpoints to evaluate, we have not reached a consensus in aging. We don't know how to predict how someone will function later in life, and we need to. ... That such a basic gap exists seems counterintuitive. After all, longevity-enhancing research has never been so prominent. ... We need to have a set of thousands of people, representing all groups, that are closely followed on health measures. They'd be tested three or four times a year, for five or 10 years. Then you'd have a good sense of the trajectory of aging ... people enrolled in the proposed study could, after several years, opt to take rapamycin. That would let researchers see whether it works in people as it does in mice. If so, they'd also have a detailed account of resulting gene and protein changes, and insight into whether rapamycin works better in some people than others. ... But take rapamycin out of the equation, and a long-term study of aging biomarkers would be suitable for institutional funding. Of course, it would still be expensive. But even a long-term study of aging in rodents would be useful, and it would also be more affordable. ... If we had a set of biomarkers that at 12 months of age predicted which mice would die younger or older, then we could shorten mouse studies to 12 months."