text: **RESULTS**In this study of 1600 EM patient records (832 [52%] female and mean [SD] age of 59.9 
  
  [18.9] years), LLM-generated handoff notes, compared with physician-written ones, had higher 
  
  ROUGE (0.322 vs 0.088), BERTScore (0.859 vs 0.796), and SCALE scores (0.691 vs 0.456), 
  
  indicating the LLM-generated summaries exhibited greater similarity and more detail. As reviewed by 
  
  3 board-certified EM physicians, a subsample of 50 LLM-generated summaries had a mean (SD) 
  
  usefulness score of 4.04 (0.86) out of 5 (compared with 4.36 [0.71] for physician-written) and mean 
  
  (SD) patient safety scores of 4.06 (0.86) out of 5 (compared with 4.50 [0.56] for physician-written). 
  
  None of the LLM-generated summaries were classified as a critical patient safety risk. 
  
  **CONCLUSIONS AND RELEVANCE**In this cohort study of 1600 EM patient medical records, 
  
  LLM-generated EM-to-IP handoff notes were determined superior compared with physician-written 
  
  summaries via conventional automated evaluation methods, but marginally inferior in usefulness 