Google announced a new tool, Google Flu Trends, that purports to track flu activity across the United States. By analyzing flu-related search trends, Google has been able to map a close relationship between the frequency of flu search queries and the number of people who are experiencing flu-like symptoms each week (according to the CDC).
Here’s a nifty chart showing the apparent correlation:
Further, by analyzing the IP addresses where these searches originate, Google can tell which geographic areas are seeing a spike in flu-related search activity, suggesting that Google may be able to detect regional outbreaks of the flu a week to 10 days before they are reported by the CDC.
Cool stuff. Two reactions:
First, while this isn’t a specific privacy threat (Google claims to be analayzing aggregate data and only sharing aggregate data with the CDC), it does expose the reality that Google tracks our searches, has the ability to isolate geographic data from IP addresses, and shares search data with third parties.
Second, while the correlation between the search queries and the CDC data seem (visually) strong, we must remember that only a certain segment of the U.S. population is using Google (the Internet, a computer) in order to seek health information. If we rely too heavily on Google Trends to determine where to target flu interventions, we might miss entire geographic areas where people simply don’t “Google” their health issues.
UPDATE: Two privacy advocacy groups, the Electronic Privacy Information Center and Patient Privacy Rights, sent a letter to Google raising privacy concerns: “The question is how to ensure that Google Flu Trends and similar techniques will only produce aggregate data and will not open the door to user-specific investigations, which could be compelled, even over Google’s objection, by court order or Presidential authority.” In the letter, they call on Google to release details on how they “anonymized” these search records.
Marc Rotenberg, executive director of the EPIC, confirms what I note above, telling the NY Times: “I think Google Flu Trends makes clear an ongoing problem with the use of Google search which has not been resolved,” and he is right to point out how this seemingly benign use of search records for flu tracking could lead us down a dangerous path: “Google is inviting public health officials to make more of search information. In doing so, it has heightened the privacy risk to people who search for health information online.”