Uncertainty Quantification

A hospital does not need a chatbot that sounds certain. It needs a system that knows when certainty would be irresponsible. That sounds obvious until one remembers how most AI demos behave: fluent answer first, caveat somewhere after the damage has already put on shoes. In clinical decision support, this is not a stylistic defect. It is an operating risk. A model can be wrong in many ways, but the most dangerous version is the confidently wrong one: the triage answer that should have been escalated, the medication suggestion that should have been checked, the risk score that looks clean only because the system has no vocabulary for doubt. ...

ICU data has a habit of disappearing exactly when analysts would prefer it to behave. A blood gas is not measured. A pressure reading arrives late. A neurological score is absent because the patient is sedated, unstable, transferred, or simply surrounded by humans doing triage instead of satisfying a data scientist’s spreadsheet fantasies. Then, after the ward has produced this imperfect record, a model is asked to infer how the patient’s physiology evolved over time. ...

A product team launches an AI assistant. The demo works. The benchmark looks respectable. The model even says “I’m confident” with the serene authority of a consultant who has never owned a pager. Then the real users arrive. Some ask ambiguous questions. Some ask adversarial questions. Some ask perfectly normal questions that happen to sit outside the model’s competence. The assistant still answers. Sometimes it refuses too often. Sometimes it refuses too late. Sometimes its confidence score is less a forecast and more a decorative sticker. ...

TL;DR for operators Models rarely fail because nobody ran a sensitivity analysis. They fail because the sensitivity analysis answered the convenient question instead of the relevant one. The paper behind gsaot introduces an R package for Optimal Transport-based global sensitivity analysis.1 Its practical value is not that it makes Sobol’ indices obsolete. It does not. The useful shift is narrower and more interesting: gsaot estimates how much the entire output distribution changes when an input is known, rather than asking only how much of the output variance can be attributed to that input. ...

TL;DR for operators LoRA and prompts are attractive because they make model adaptation feel almost too easy: add a few examples, attach a small adapter, nudge the model into a domain, and call it customised. The uncomfortable part is that adaptation changes not only what a model says, but how confidently it says it. A compliance assistant that becomes slightly more domain-specific but far more overconfident has not been improved. It has been promoted beyond its competence, a classic corporate move. ...