The problem of prevention

Most people aspire to healthy living but staying healthy and preventing illness carry a cost—counted in money, time, effort, information, trust, and willpower. The principles of prevention can be framed as a conditional, testable hypothesis: prevention is more likely to be favoured when individuals or populations can choose, given the constraints presented in any setting, a low-cost, high-efficacy method of averting a large, probable, imminent threat to health. The decisions that people make about health depend, not only on quantified options, risks, hazards, and timing, but also on the incentives, motives, powers, and values of everyone who has a stake in the outcome—individuals, governments, non-governmental organizations, businesses, and others. Data presented in this chapter suggest that more money and effort are invested in prevention today than is commonly thought, but the enormous, persistent, avoidable burden of ill health is a reason to seek ways of investing still more.