…but I suspect Flash will find this very interesting:
But can search query trends provide an accurate, reliable model of real-world phenomena?
We have found a close relationship between how many people search for flu-related topics and how many people actually have flu symptoms. Of course, not every person who searches for “flu” is actually sick, but a pattern emerges when all the flu-related search queries from each state and region are added together. We compared our query counts with data from a surveillance system managed by the U.S. Centers for Disease Control and Prevention (CDC) and discovered that some search queries tend to be popular exactly when flu season is happening. By counting how often we see these search queries, we can estimate how much flu is circulating in various regions of the United States.
During the 2007-2008 flu season, an early version of Google Flu Trends was used to share results each week with the Epidemiology and Prevention Branch of the Influenza Division at CDC. Across each of the nine surveillance regions of the United States, we were able to accurately estimate current flu levels one to two weeks faster than published CDC reports.
This graph shows five years of query-based flu estimates for the Mid-Atlantic region of the United States, compared against influenza surveillance data provided by CDC’s U.S. Influenza Sentinel Provider Surveillance Network. As you can see, estimates based on Google search queries about flu are very closely matched to a flu activity indicator used by CDC. Of course, past performance is no guarantee of future results. Our system is still very experimental, so anything is possible, but we’re hoping to see similar correlations in the coming year.