ROR (Reporting Odds Ratio)

The Reporting Odds Ratio (ROR) is a pharmacovigilance statistic used in disproportionality analysis of adverse event databases—such as the FDA's FAERS—to measure whether a specific drug-event combination is reported more frequently than would be expected by chance across all reports in the database. In mass tort litigation, plaintiff firms and their scientific consultants use ROR values as early signal-detection evidence to help establish that a drug or device was associated with a particular adverse outcome well before regulatory action was taken. A statistically significant ROR (typically accompanied by a lower bound of the confidence interval above 1.0) can support arguments about manufacturer notice and failure to warn. ROR data are generally used as hypothesis-generating signals rather than standalone proof of causation, and their evidentiary weight is typically evaluated alongside epidemiological studies and internal company documents.