Google Flu Trends | How does this work?

Added By Infochimps

Google Flu Trends uses aggregated Google search data to estimate current flu activity around the world in near real-time. This site has a visualization of Google Flu Trends in comparison to the CDC’s data. There is also a link to a dataset of Google Flu Trends weekly influenza activity estimates for the world, from December 2002 to the present.

Each week, millions of users around the world search for health information online. As you might expect, there are more flu-related searches during flu season, more allergy-related searches during allergy season, and more sunburn-related searches during the summer. Google has 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 are added together. Google compared their query counts with traditional flu surveillance systems and found that many search queries tend to be popular exactly when flu season is happening. By counting how often they see these search queries, they estimated how much flu is circulating in different countries and regions around the world.