You have 100 doses of a vaccine against a deadly strain of influenza that is sweeping the country, with no prospect of obtaining more. Standing in line are 100 schoolchildren and 100 elderly people. The elderly people are more likely to die if they catch the flu than the schoolchildren are. But the elderly people have relatively fewer years left to live, whereas the schoolchildren have their whole lives ahead of them. Which group do you vaccinate? Describe each step in your decision-making process.