Cascading classifiers for named entity recognition in clinical notes

  • Authors:
  • Yefeng Wang;Jon Patrick

  • Affiliations:
  • University of Sydney, Australia;University of Sydney, Australia

  • Venue:
  • WBIE '09 Proceedings of the Workshop on Biomedical Information Extraction
  • Year:
  • 2009

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Abstract

Clinical named entities convey great deal of knowledge in clinical notes. This paper investigates named entity recognition from clinical notes using machine learning approaches. We present a cascading system that uses a Conditional Random Fields model, a Support Vector Machine and a Maximum Entropy to reclassify the identified entities in order to reduce misclassification. Voting strategy was employed to determine the class of the recognised entities between the three classifiers. The experiments were conducted on a corpus of 311 manually annotated admission summaries form an Intensive Care Unit. The recognition of 10 types of clinical named entities using 10 fold cross-validation achieved an overall results of 83.3 F-score. The reclassifier effectively increased the performance over stand-alone CRF models by 3.35 F-score.