Comparing Two Model Designs for Clinical Note Generation; Is an LLM a Useful Evaluator of Consistency?
Nathan Brake, Thomas Schaaf
TL;DR
This study compares two PEGASUS-X–based designs for generating SOAP notes from DoPaCo transcripts: GENMOD, which produces the full note in one pass, and SPECMOD, which trains separate models for each section. Using automatic metrics (ROUGE, Factuality) and human plus Llama2-based evaluations of consistency, the authors find that the two designs yield similar overall automatic performance, while GENMOD often shows stronger internal consistency for age, gender, and body-part references. Llama2 demonstrates potential as a scalable evaluator aligned with human judgments for certain criteria, though coherence assessments remain challenging. The work highlights how conditioning each new section on prior sections improves consistency and points to LLM-based evaluation as a promising direction for scaling quality assessment in clinical note generation.
Abstract
Following an interaction with a patient, physicians are responsible for the submission of clinical documentation, often organized as a SOAP note. A clinical note is not simply a summary of the conversation but requires the use of appropriate medical terminology. The relevant information can then be extracted and organized according to the structure of the SOAP note. In this paper we analyze two different approaches to generate the different sections of a SOAP note based on the audio recording of the conversation, and specifically examine them in terms of note consistency. The first approach generates the sections independently, while the second method generates them all together. In this work we make use of PEGASUS-X Transformer models and observe that both methods lead to similar ROUGE values (less than 1% difference) and have no difference in terms of the Factuality metric. We perform a human evaluation to measure aspects of consistency and demonstrate that LLMs like Llama2 can be used to perform the same tasks with roughly the same agreement as the human annotators. Between the Llama2 analysis and the human reviewers we observe a Cohen Kappa inter-rater reliability of 0.79, 1.00, and 0.32 for consistency of age, gender, and body part injury, respectively. With this we demonstrate the usefulness of leveraging an LLM to measure quality indicators that can be identified by humans but are not currently captured by automatic metrics. This allows scaling evaluation to larger data sets, and we find that clinical note consistency improves by generating each new section conditioned on the output of all previously generated sections.