Fig. 3.

Receiver operating characteristic curves for the WEB-RADR reference set, using data from April 2012 up to March 2015 for both positive and negative controls. ‘Social 0.X’ means Twitter/Facebook data with a post-level indicator score threshold of 0.X. The area under the curve ranges between 0.64 and 0.69 in VigiBase, and is 0.55 or lower in all social media datasets. The diagonal represents a random classifier. For the common algorithm IC₀₂₅ > 0, sensitivity in VigiBase is 0.38 (at specificity 0.83). For patient forum posts, sensitivity is 0.14 (at specificity 0.88); and for Twitter/Facebook, sensitivity is 0.08 or lower. IC Information Component, PRR Proportional Reporting Ratio