title: Hiding in plain sight: use of realistic surrogates to reduce exposure of protected health information in clinical text.
abstract: OBJECTIVE
  Secondary use of clinical text is impeded by a lack of highly effective, low-cost de-identification methods. Both, manual and automated methods for removing protected health information, are known to leave behind residual identifiers. The authors propose a novel approach for addressing the residual identifier problem based on the theory of Hiding In Plain Sight (HIPS).
  
  
  METHODS
  HIPS relies on obfuscation to conceal residual identifiers. According to this theory, replacing the detected identifiers with realistic but synthetic surrogates should collectively render the few 'leaked' identifiers difficult to distinguish from the synthetic surrogates. The authors conducted a pilot study to test this theory on clinical narrative, de-identified by an automated system. Test corpora included 31 oncology and 50 family practice progress notes read by two trained chart abstractors and an informaticist.
  
  
  RESULTS
  Experimental results suggest approximately 90% of residual identifiers can be effectively concealed by the HIPS approach in text containing average and high densities of personal identifying information.
  
  
  CONCLUSIONS
  This pilot test suggests HIPS is feasible, but requires further evaluation. The results need to be replicated on larger corpora of diverse origin under a range of detection scenarios. Error analyses also suggest areas where surrogate generation techniques can be refined to improve efficacy.
  
  
  CONCLUSIONS
  If these results generalize to existing high-performing de-identification systems with recall rates of 94-98%, HIPS could increase the effective de-identification rates of these systems to levels above 99% without further advancements in system recall. Additional and more rigorous assessment of the HIPS approach is warranted.
authors: Group Health Research Institute, Seattle, WA 98101, USA. carrell.d@ghc.org
authors: David
authors: D
authors: Carrell
authors: Bradley
authors: B
authors: Malin
authors: John
authors: J
authors: Aberdeen
authors: Samuel
authors: S
authors: Bayer
authors: Cheryl
authors: C
authors: Clark
authors: Ben
authors: B
authors: Wellner
authors: Lynette
authors: L
authors: Hirschman
mesh_terms: D035843:Biomedical Research / Q000706:statistics & numerical data; D016494:Computer Security; D003219:Confidentiality; D003625:Data Collection; D057286:Electronic Health Records; D006801:Humans; D033181:Information Dissemination; D009323:Natural Language Processing; D010865:Pilot Projects; D014481:United States