[Infowarrior] - Google Uses Searches to Track Flu’s Spread

[Richard Forno]

November 12, 2008
Google Uses Searches to Track Flu’s Spread
By MIGUEL HELFT

http://www.nytimes.com/2008/11/12/technology/internet/12flu.html?_r=1&hp=&oref=slogin&pagewanted=print

SAN FRANCISCO — What if Google knew before anyone else that a fast- 
spreading flu outbreak was putting you at heightened risk of getting  
sick? And what if it could alert you, your doctor and your local  
public health officials before the muscle aches and chills kicked in?

That, in essence, is the promise of Google Flu Trends, a new Web tool  
that Google.org, the company’s philanthropic unit, unveiled on  
Tuesday, just as flu season is getting underway in the United States.

Google Flu Trends is based on the simple idea that people who are  
feeling sick will probably turn to the Web for information, typing  
things like “flu symptoms” or “muscle aches” into Google. The service  
tracks such queries and charts their ebb and flow, broken down by  
regions and states.

Early tests suggest that the service may be able to detect regional  
outbreaks of the flu between a week and 10 days before they are  
reported by the Centers for Disease Control and Prevention. Some  
public health experts say that could help accelerate the response of  
doctors, hospitals and public health officials to a nasty flu season,  
reducing the spread of the disease and, potentially, saving lives.

It could also offer a dose of comfort to stricken individuals in  
knowing that a bug is going around.

“This could conceivably provide as early a warning of an outbreak as  
any system,” said Lyn Finelli, lead for surveillance at the influenza  
division of the C.D.C. Ms. Finelli noted that people often search the  
Internet for medical information before they call their doctor.

“The earlier the warning, the earlier prevention and control measures  
can be put in place, and this could prevent cases of influenza,” Ms.  
Finelli said. Between 5 percent and 20 percent of the nation’s  
population contracts the flu each year, Ms. Finelli said, leading to  
an average of roughly 36,000 deaths.

Google Flu Trends is the latest indication that the words typed into  
search engines like Google can be used to track the collective  
interests and concerns of millions of people, and even to forecast the  
future.

“This is an example where Google can use the incredible systems that  
we have to come up with an interesting, predictive result,” said Eric  
E. Schmidt, Google’s chief executive. “From a technological  
perspective, it is the beginning.”

For now the service only covers the United States, but Google is  
hoping to eventually use the same technique to help track influenza  
and other diseases worldwide.

The premise behind Google Flu Trends has been validated by an  
unrelated study indicating that the data collected by Yahoo, Google’s  
main rival in Internet search, can also help with early detection of  
the flu.

“In theory, we could use this stream of information to learn about  
other disease trends as well,” said Philip M. Polgreen, assistant  
professor of medicine and epidemiology at the University of Iowa and a  
co-author of the study based on Yahoo’s data.

Still, some public health officials note that many health departments  
already use other techniques, like gathering data from visits to  
emergency rooms, to keep daily tabs on disease trends in their own  
communities.

“We don’t have any evidence that this is more timely than our  
emergency room data,” said Farzad Mostashari, assistant commissioner  
of New York City’s Department of Health and Mental Hygiene.

If Google provided health officials with details of the inner workings  
of the system so that it could be validated scientifically, the data  
could serve as an additional way to detect influenza that is free and  
may prove valuable, said Mr. Mostashari, who is also chairman of the  
International Society for Disease Surveillance.

A paper on the methodology behind Flu Trends is expected to be  
published in a future issue of the journal Nature.

Researchers have long said that the data sprinkled throughout the Web  
amounts to a form of “collective intelligence” that could be used to  
make predictions. There are commercial Web sites that mine this  
information to predict airfares or home prices.

But the data collected by search engines is particularly powerful,  
because the keywords and phrases that people type into search engines  
represent their most immediate intentions. People may search for  
“Kauai hotel” when they are planning a vacation and for “foreclosure”  
when they get in trouble with their mortgage. Those queries express  
the world’s collective desires and needs, its wants and likes.

Internal research at Yahoo suggests that increases in searches for  
certain terms can help forecast what technology products will be hits,  
for instance. Yahoo itself has begun using search traffic to help it  
decide what material to feature on its home page. It analyzes what its  
users are interested in and then programs its Web site accordingly.

Two years ago, Google began opening up its search data trove through  
Google Trends, a tool that allows anyone to track the relative  
popularity of search terms. Google also offers more sophisticated  
search traffic tools that marketers can use to fine-tune advertising  
campaigns. And internally it has tested the use of search data to  
reach conclusions about economic, marketing and entertainment trends.  
It found both promises and limitations.

“This works remarkably well, but tends to miss ‘turning points,’ times  
when the data changes direction,” said Hal Varian, Google’s chief  
economist.

Yahoo’s head of research, Prabhakar Raghavan, also said search data  
could be immensely valuable for forecasters and scientists, but  
concerns about privacy have generally stopped the company from sharing  
it with outside academics.

Google Flu Trends gets around privacy pitfalls by relying only on  
aggregated data that cannot be used to identify individual searchers.  
To develop the service, Google’s engineers devised a basket of  
keywords and phrases related to the flu, including thermometer, flu  
symptoms, muscle aches, chest congestion and many others. Google then  
dug into its database, extracted five years of data on those queries  
and mapped the data onto the C.D.C.’s reports of “influenza-like  
illness,” which the agency compiles based on data from labs, health  
care providers, death certificates and other sources. Google found an  
almost perfect correlation between its data and the C.D.C. reports.

“We know it matches very, very well in the way flu developed in the  
last year,” said Larry Brilliant, executive director of Google.org.  
Ms. Finelli of the C.D.C. and Mr. Brilliant both cautioned that the  
data needed to be monitored to ensure that the correlation with flu  
activity remained valid.

Other people have tried to use information collected from Internet  
users for public health purposes. A Web site called whoissick.org, for  
instance, invites people to report about what ails them and  
superimposes the results on a map. But the site has received little  
traffic, so its usefulness is limited.

HealthMap, a project affiliated with Children’s Hospital Boston and  
Harvard Medical School, scours the Web for news articles, blog posts  
and electronic newsletters to create a map that tracks emerging  
infectious diseases around the world. It is backed by Google.org,  
which counts the detection and prevention of diseases as one of its  
main philanthropic objectives.

But Google Flu Trends appears to be the first public project that uses  
the powerful database of a search engine to track the emergence of a  
disease.

“This seems like a really clever way of using data that is created  
unintentionally by the users of Google to see patterns in the world  
that would otherwise be invisible,” said Thomas Malone, a professor at  
the M.I.T. Sloan School of Management. “I think we are just scratching  
the surface of what’s possible with collective intelligence.”