# Non-Water Explicit Solvation Holdout Methodology

Snapshot date: `2026-03-07`

This artifact summarizes strict repeated-holdout validation for the native explicit non-water carrier models:
- methanol
- ethanol
- acetonitrile
- DMSO

Protocol:
- stratified repeated holdout by chemotype
- 64 repeats
- 25% holdout fraction per repeat
- case-level anchor features built from the production non-water solvation model
- solvent-local and cross-solvent transfer models blended under solvent-specific gating rules

Reported fields:
- split mean absolute error in kcal/mol
- split standard deviation in kcal/mol
- worst chemotype mean absolute error for categories with at least 3 unique cases
- pass/fail flag for the `0.5 kcal/mol` worst-category threshold

This packet is sanitized for publication and does not include internal script paths, internal tuning notes, or unpublished implementation details.