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Monday, March 06, 2006

Anonymizing data files for OA

Bruce A. Beckwith and three co-authors, Development and evaluation of an open source software tool for deidentification of pathology reports, BMC Medical Informatics and Decision Making, March 6, 2006. Abstract (provisional):
Background. Electronic medical records, including pathology reports, are often used for research purposes. Currently, there are few programs freely available to remove identifiers while leaving the remainder of the pathology report text intact. Our goal was to produce an open source, Health Insurance Portability and Accountability Act (HIPAA) compliant, deidentification tool tailored for pathology reports. We designed a three-step process for removing potential identifiers. The first step is to look for identifiers known to be associated with the patient, such as name, medical record number, pathology accession number, etc. Next, a series of pattern matches look for predictable patterns likely to represent identifying data; such as dates, accession numbers and addresses as well as patient, institution and physician names. Finally, individual words are compared with a database of proper names and geographic locations. Pathology reports from three institutions were used to design and test the algorithms. The software was improved iteratively on training sets until it exhibited good performance. 1800 new pathology reports were then processed. Each report was reviewed manually before and after deidentification to catalog all identifiers and note those that were not removed.

Results. 1254 (69.7 %) of 1800 pathology reports contained identifiers in the body of the report. 3439 (98.3%) of 3499 unique identifiers in the test set were removed. Only 19 HIPAA-specified identifiers (mainly consult accession numbers and misspelled names) were missed. Of 41 non-HIPAA identifiers missed, the majority were partial institutional addresses and ages. Outside consultation case reports typically contain numerous identifiers and were the most challenging to deidentify comprehensively. There was variation in performance among reports from the three institutions, highlighting the need for site-specific customization, which is easily accomplished with our tool.

Conclusions. We have demonstrated that it is possible to create an open-source deidentification program which performs well on free-text pathology reports.

Comment. What's the OA connection? If researchers in medicine and the social sciences can anonymize their data files, then they can deposit them in OA repositories without violating the privacy of patients or research subjects. An open-source tool that does most of the work, and only needs fine-tuning for specific data formats, should remove the privacy roadblock barring OA to mountains of useful and reusable research data.