A machine learning model using clinical notes to identify physician fatigue.

Clinical notes should capture important information from a physician-patient encounter, but they may also contain signals indicative of physician fatigue. Using data from 129,228 emergency department (ED) visits, we train a model to identify notes written by physicians who are likely to be tired: those who worked ED shifts on at least 5 of the prior 7 days. In a hold-out set, the model accurately identifies notes written by such high-workload physicians. It also flags notes written in other settings with high fatigue: overnight shifts and high patient volumes. When the model identifies signs of fatigue in a note, physician decision-making for that patient appears worse: yield of testing for heart attack is 19% lower with each standard deviation increase in model-predicted fatigue. A key feature of notes written by fatigued doctors is the predictability of the next word, given the preceding context. Perhaps unsurprisingly, because word prediction is the core of how large language models (LLMs) work, we find that predicted fatigue of LLM-written notes is 74% higher than that of physician-written ones, highlighting the possibility that LLMs may introduce distortions in generated text that are not yet fully understood.