November 3, 2023

Comparing Statistical Significance with Clinical Relevance: The Fragility Index vs. The Relative Risk Index

A recent study compared different metrics for evaluating the fragility and clinical relevance of research findings. The fragility index, which measures how easily p-values flip from significant to nonsignificant, strongly correlated with p-values in simulated 2×2 contingency tables. This suggests the fragility index provides minimal insight beyond p-values alone. In contrast, the relative risk index, which quantifies divergence from therapeutic equivalence, showed only weak correlation with p-values. The relative risk index appears to assess something distinct from statistical significance, more closely related to clinical relevance. This novel metric warrants further real-world testing but may provide a complementary tool to p-values and fragility indices for appraising research robustness.

Citation: Heston TF. Statistical significance versus clinical relevance: a head-to-head comparison of the fragility index and relative risk index. Cureus. 2023;15(10):e47741. DOI:10.7759/cureus.47741.