Predicting molecular behavior is key in drug discovery, but examples are scarce. (LLMs) read a molecule's structure as text and predict a property, also stating their confidence. Can that confidence be trusted?
The study tested several LLMs on multiple datasets, giving each a small set of examples (up to thirty) and asking for predictions with uncertainties. These were compared to many classical models. The researchers ensured the data was not memorized.
On clean data, the best LLM beat every classical model using just that many examples. But its stated uncertainty ranked errors only moderately, with a correlation of 0.46, similar to classical uncertainties. Selecting the most confident half helped rarely, so self-reported uncertainty is of limited value.
