# Beyond Snap Ratio Preprint 2.1 — clarification notes Release date: 2026-09-04 Git tag: `beyond-snap-ratio-v2.1` Version DOI: All-version concept DOI: Research-compendium DOI: ## Clarified index arithmetic Preprint 2.1 makes the released index construction explicit: ```text Weight Index = fleet percentile(full-precision cohort collapse force) Tactility Index = fleet percentile(full-precision cohort force Drop) ``` Each index is a single-input coordinate in the frozen 68-dome reference fleet. Pearson and Spearman coefficients summarize associations; neither is an arithmetic weight. The legacy analysis field `rho_weighted_family_composite_spearman_rho` describes a rejected candidate- composite diagnostic, not either released index. ## Press work to force-wall Press work to force-wall is correctly sixth in the perceived-weight screen: - `rho = 0.817380609886974`; - 95% BCa interval `[0.648791394920568, 0.913590454630411]`; - fourth-ranked Drop `rho = 0.8223999523`; and - fifth-ranked Drop rate `rho = 0.8181528164`. The near-tie is resolved by full-precision values. The metric remains a separate full-stroke-effort descriptor rather than an index input because it uses the assembly-defined detected force-wall endpoint, can be unavailable when no wall is detected, and is highly redundant in the pilot with collapse force (`rho = 0.900000`) and pre-collapse work (`rho = 0.943077`). The pilot does not establish an independent contribution that warrants adding it to the single-input Weight Index. ## Scientific and software boundary This is an editorial clarification. It changes no force curve, subjective observation, statistical estimate, figure, index input, reference-fleet value, percentile calculation, model identifier, or protected Force Curve Bench runtime byte. Preprint 2.0 remains an immutable archival version. The 21-file Zenodo payload passed deterministic checksum validation. The 54-page PDF SHA-256 is `1de8e71e32b557e4cffeffe03ffb13a6326789e99b04890147043f6f7728c862`; the publication-manifest SHA-256 is `4c9e664529f70ccb35573daab6a0248d8642d04534aef02b6b87aca8359b1686`.