Word search performance for diagnoses of equine surgical colics in free-text electronic patient records

The objectives of the current project were to: (1) identify limitations of search sensitivity and positive predictive value (PPV) for free-text surgical diagnoses included in electronic patient records maintained at the University of California, Davis, Veterinary Medical Teaching Hospital (VMTH), (2) develop procedural or programmable recommendations for removing these limitations, and (3) provide guidelines for effective search strategies for users performing aggregate searches using the VMTH clinical information system. Search sensitivity corresponds to detection sensitivity (the capacity of a search term to 'identify' a relevant document) and search PPV indicates the proportion of retrieved documents that are relevant. All horses submitted to the VMTH for a gastrointestinal (GI) disorder requiring surgical intervention in 1995 were identified using procedure codes for billing purposes and stored in the electronic patient record. Patient records and surgical reports were reviewed for causes of GI disorders, and variation in naming of these disorders. Key word searches were performed for four GI disorders, and search performance was evaluated by estimating search sensitivity and PPV. Search sensitivity ranged from 33% to 98%, and PPV ranged from 2% to 74%. The procedural recommendation that would likely have the greatest influence on minimizing these search limitations would be more uniform naming of GI disorders. This would free searchers from having to anticipate all of the exact word combinations that could be used in the relevant documents, and also minimize retrieval of irrelevant documents.