Twitter users send around 500 million tweets a day, an endless fire hose of information about how people feel, what they’re doing, what they know and where they are.
For epidemiologists and public health officials, it’s a potential gold mine of data, a possible way to track where disease is breaking out and how it spreads, as well as how best to help – but only if they can figure out how to find the useful signal amid all that noise.
The question is: How do you take these billions of messages, find the useful information and get it to people who can respond? says Mark Dredze, an assistant professor of computer sciences at Johns Hopkins University, who studies computational linguistics.
That’s a very big question, one whose difficulty has pushed many researchers away from the idea of using Twitter data, which they say is too messy and too uncontrolled compared with traditional methods of collecting health data, such as surveys and analyses of hospital visits. Others argue that, once we learn to effectively harness the data, Twitter’s very messiness (including the impulse to tweet what you had for breakfast or how annoying your runny nose is) will be what makes it an invaluable resource.
It’s like a pulse on the world, because people will just tweet whatever, whenever, explains Christophe Girraud-Carrier, an associate professor of computer science at Brigham Young University, who studies what he and his colleagues have dubbed computational health science. Poll answers are filtered by perception or memory; on Twitter, we’re actually observing real behavior in real time.
Using Twitter data has other advantages, Dredze says. For starters, it’s faster: It can take the Centers for Disease Control and Prevention about two weeks to publish findings, Dredze says.
Those numbers can additionally be delayed by the fact that a sickness doesn’t show up in statistics until someone goes to the hospital or does something else that causes the ailment to be reported.
Twitter, on the other hand, might reflect it the first morning someone wakes up with a sore throat. Speed can be a big advantage when tracking epidemics and emerging diseases, says Taha Kass-Hout, director of the CDC’s Division of Informatics Solutions and Operations. An emerging disease from Southeast Asia can be in your backyard in 12 to 14, maybe 24 hours. So you have to respect that.
Twitter can also provide a more detailed picture of where disease is breaking out, since many tweets are tagged with their locations. That, coupled with faster data, could help keep hospitals and clinics from getting overwhelmed in the middle of an outbreak: Even a few days’ notice that disease occurrences are spiking can mean being prepared with extra beds, staff or medicine. Detailed, location-specific data can also identify clumps of noncommunicable diseases – cardiovascular disease or Type II diabetes, for example – allowing health officials to focus education efforts in the areas that need it most.
Twitter is also in increasingly wide use, including in countries that don’t have effective public health tracking agencies. In that case, anything Twitter can provide – whether it’s fast, slow whatever – is really valuable, Dredze says.
Those advantages, coupled with the fact that researchers are getting better at tracking and analyzing useful information, mean that consensus is forming in the public health and health care communities that we really need to pay attention to social media, Kass-Hout says. However, he stresses that social media information is a complementary tool, rather than a replacement for more traditional methods of gathering information.
It also depends on validation, the ability to prove that data collected through Twitter have real-world accuracy.