Deterministic vs. Probabilistic: Best Practices for Patient Matching Based on a Comparison of Two Implementations.

In order to successfully share patient data across multiple systems, a reliable method of linking patient records across disparate organizations is required. In Canada, within the province of Ontario, there are four centralized diagnostic imaging repositories (DIRs) that allow multiple hospitals and independent health facilities (IHF) to send diagnostic images and reports for the purpose of sharing patient data across the region (Nagels et al. J Digit Imaging 28: 188, 2015). In 2017, the opportunity to consolidate the two regional DIRs that share the south-central and southeast area of the province was reviewed. The two DIRs use two different methods for patient matching. One uses a deterministic match based on one specific value, while the other uses a probabilistic scorecard that weighs a variety of patient demographics to assess if the patients are a match. An analysis was conducted to measure how a patient identity domain that uses a deterministic approach would compare to the accepted "standard." The intention is to review the analysis as a means of identifying interesting insights in both approaches. For the purpose of this paper, the two DIRs will be referred to as DIR1 and DIR2.