It turns out that by charting the number of Google searches over time on flu, you can generate a very accurate time-series of the number of cases of flu itself; see the chart above as an example The obvious explanation is that when people feel the flu coming on and/or when they already have it, they want to familiarize themselves with what to expect and how to treat it, so they search online for information.
This is pretty cool, in a wonkish way. Moreover, it’s even useful:
bq. So why bother with estimates from aggregated search queries? It turns out that traditional flu surveillance systems take 1-2 weeks to collect and release surveillance data, but Google search queries can be automatically counted very quickly. By making our flu estimates available each day, Google Flu Trends may provide an early-warning system for outbreaks of influenza. For epidemiologists, this is an exciting development, because early detection of a disease outbreak can reduce the number of people affected. If a new strain of influenza virus emerges under certain conditions, a pandemic could emerge and cause millions of deaths (as happened, for example, in 1918). Our up-to-date influenza estimates may enable public health officials and health professionals to better respond to seasonal epidemics and – though we hope never to find out – pandemics.
To find out more, click here.
[Hat tips to Bryan Boulier and Bob Goldfarb]