Google Flu Trends

Google Flu Trends is a web service operated by Google. It uses aggregated Google search data to estimate influenza activity. Google Flu Trends was launched in November 2008 and covered 25 countries initially. The service was discontinued in August 2015.

Overview

Google Flu Trends was a service provided by Google.org, the charitable arm of Google. The service aimed to provide real-time estimates of the prevalence of flu-like illness in various regions around the world by analyzing the volume of certain search queries. The underlying assumption was that people who are feeling ill are more likely to search for information related to their symptoms, and that this information can be used to estimate the overall level of flu activity in a given region.

Methodology

The methodology behind Google Flu Trends involved the use of big data and machine learning algorithms. Google collected anonymized search data and used an algorithm to identify which search terms were correlated with the official flu data provided by the Centers for Disease Control and Prevention (CDC). The algorithm was trained on several years of historical flu data and search data, and was updated periodically to account for changes in search behavior.

Accuracy and Criticism

While Google Flu Trends was initially praised for its potential to provide real-time estimates of flu activity, it faced criticism for its accuracy. A study published in the journal Science in 2014 found that Google Flu Trends overestimated the prevalence of flu in the 2012-2013 flu season by a factor of two. The authors of the study suggested that the algorithm may have been confounded by media coverage of the flu, which could have led to an increase in flu-related search queries that was not related to an actual increase in flu activity.

Discontinuation

Google discontinued Google Flu Trends in August 2015. The company stated that it was transitioning from offering its own flu estimates to making the underlying data available to researchers, health organizations, and other groups. The data is now part of Google's Google Health initiative.

See also

• Google Dengue Trends
• Google Health
• Public health surveillance