Perspective: ML models see representations, not molecules, so demand accountability
- A Perspective (no new dataset or benchmark) examining what ML models actually receive across structural formulas, SMILES, fingerprints, graphs, conformers, simulated ensembles and language-model tokens.
- It argues that both the molecule and the bioactivity label are representations, so tautomer ambiguity, stereochemistry, activity cliffs, noisy labels and generative failures reflect this double reduction.
- The proposed standard is accountability: explicit entity definitions, assay provenance, calibrated uncertainty and prospective testing, with controlled perturbation tests to separate representational loss from model limits.
Most of this will be familiar to anyone who has watched a model flip on a re-enumerated SMILES, but the perturbation-test idea is the usable part. On our own project I'd run it before trusting any benchmark gain: randomize SMILES, swap tautomer or protonation states, then see whether error tracks the representation or the model. Without prospective data, though, a Perspective can't tell us which fixes matter.
📄 Paper · Journal of Chemical Information and Modeling ↗ Ceci n’est pas le benzène: The Treachery of Chemical Representations in Machine Learning for Drug Discovery