Fragility of Assumptions: Letter to the Editor

This deposit contains the published Letter to the Editor from the Orthopaedic Journal of Sports Medicine (2026), which identifies fundamental flaws in traditional fragility assessments. The author argues that the classic Fragility Index (FI) is inherently biased because it assumes instability resides only in the trial arm with fewer events.As a solution, this letter introduces the Relative Risk Index (RRI), a model-free metric that quantifies the "residual" change required to achieve treatment neutrality. This work represents the conceptual foundation of the Risk Quotient (RQ) and the Neutrality Boundary Framework (NBF), which have since been formalized into the complete p–fr–nb statistical evidence triplet.This document is essential for understanding the transition from P-value-centric fragility to geometric robustness in clinical evidence evaluation.