Pearson product moment correlation coefficient (‘r’) between prescription sales data from a large drug retailing pharmacy chain in the United States and Google Flu trends data and CDC ILI data.

Pearson product moment correlation coefficient (‘r’) between (1) The aggregate counts of scripts for four drugs commonly prescribed for influenza namely: Amantadine, Oseltamivir, Rimantadine, and Zanamivir expressed as scripts per 100,000 total scripts and the Google trends data Influenza-like Illness (ILI) cases per 100,000 physicians visits:2007–2011, year by year and aggregate 2007–2011 and (2) The prescription sales data for 2007 from the above prescription sales data and % unweighted ILI data for 2007 from CDC's Outpatient Influenza-like Illness Surveillance Network (ILINet).