As you have heard in the news, there has been an outbreak of swine flu in Mexico and the United States. There is a possibility that this situation might develop into a pandemic if the virus continues to spread around the globe. The news media report excessively about this threat, and while health officials urge people to stay calm, there is an increased level of anxiety in the population.

Models have predicted that when a disease breaks out, changes in behavior in response to an outbreak, and in particular in response to information about an outbreak, can alter the progression of an epidemic. While this makes intuitive sense, there is no good data to test such a hypothesis. One of the