Reproducible QSAR Modeling in Computational Cheminformatics: From Molecular Descriptors to Model Diagnostics
1. Introduction and Motivation Quantitative Structure–Activity Relationship (QSAR) modeling represents one of the earliest and most enduring attempts to formalize the relationship between chemical structure and biological or physicochemical activity. At its core, QSAR is founded on a deceptively simple premise: that measurable properties derived from molecular structure encode information relevant to how a compound behaves in a given experimental or biological context. Despite its long history, QSAR remains highly relevant in contemporary computational chemistry, cheminformatics, and early-stage drug discovery, particularly as a baseline framework against which more complex machine-learning approaches are evaluated. However, while the conceptual foundations of QSAR are widely taught, the practical construction of a QSAR pipeline that is methodologically sound, reproducible, and diagnostically transparent is far less frequently demonstrated in a complete and auditable manner. Many publi...