NBMEcalc Step 2 CK Practice-Assessment Interpretation Model: Methodology, Intended Use, Limitations, and Prospective Validation Plan

NBMEcalc is an independent browser-based educational planning tool that combines user-entered practice-assessment results into a Step 2 CK point estimate, a model-generated planning interval, and a heuristic estimate of pass probability. This developer-authored technical report documents model version v1.1 as implemented on July 17, 2026. It describes supported input families, internal mappings, source and recency weights, aggregation formulas, intended uses, inappropriate uses, data-governance considerations, and known limitations. The mappings and source adjustments are internal assumptions, not official conversions. No reproducible outcome cohort, independent holdout evaluation, or peer-reviewed validation is currently published. The report therefore defines a prospective validation protocol covering temporal model freezing, prediction error, interval coverage, probability calibration, subgroup reporting, missing data, and version control. NBMEcalc is not affiliated with, endorsed by, or sponsored by NBME, USMLE, FSMB, UWorld, or AMBOSS.