The fragility index is a statistical metric used primarily in the medical literature to assess study results.
The result of scientific studies is said to be statistically significant if the calculated probability of a type I error (assumption of a correlation that does not really exist) is below the arbitrarily chosen but generally accepted limit of 5%.
Study results that meet these significance criteria can be published more easily and in more highly ranked journals (publication bias).
The fragility index describes the extent to which the attribution of statistical significance is subject to random influences.
It indicates the number of patients or subjects whose results would have to change in order to alter the statistical interpretation of the study.