fastml: Guarded Resampling Workflows for Safer Automated Machine Learning in R

ArXi:2604.05225v1 Announce Type: cross Preprocessing leakage arises when scaling, imputation, or other data-dependent transformations are estimated before resampling, inflating apparent performance while remaining hard to detect. We present fastml, an R package that provides a single-call interface for leakage-aware machine learning through guarded resampling, where preprocessing is re-estimated inside each resample and applied to the corresponding assessment data.