A statistical signature in the Big G discrepancy: gas-pressure documentation tracks measurement residuals

This preprint reports a framework-agnostic statistical analysis of published measurements of Newton's gravitational constant G. Across an audited corpus of Big G measurements, experiments documenting gas-pressure systematic checks exhibit substantially smaller absolute residuals relative to CODATA than experiments without such documentation. The analysis reports Welch, Mann-Whitney, and exact permutation tests, plus leave-one-out robustness checks. The result supports a systematics-dominated reading of part of the Big G discrepancy and motivates prospective tracking of the Birge ratio as new measurements are published. This release does not propose a new value of G, does not claim a new theory of gravity, and excludes proprietary engineering implementations, patent-directed apparatus designs, and unpublished calibration protocols. Disclosure: AI tools were used for drafting assistance, code generation, formatting, and internal consistency checks. The author is solely responsible for the study design, analysis choices, verification, conclusions, and final manuscript.