Measuring Strength of Randomized Clinical Trials

The outcomes of randomized clinical trials (RCTs) are commonly assessed using the Fragility Index (FI). Althouh the FI offers supplementary information to the p-value, it comes with inherent limitations. This study reexamines the fragility analysis, placing it within a more comprehensive framework to enhance its ability to complement p-value information reliably. Drawing on the fundamental principles of fragility analysis, we introduce a Strength Index (SI) for RCTs (Quatto et al. Beyond the fragility index. Mimeo (2023)). On this basis, we recommend a triplet of indicators for the analysis of strength. In particular, the SI is applicable in both significant and non-significant cases, offering straightforward calculation and addressing some of the issues associated with the FI. Being a normalized index, we propose a threshold for its assessment in practical applications. Importantly, the SI is utilized in the examination of recent clinical trials, providing a valuable alternative perspective.