Accurate linking of an individual’s medical records from disparate sources within and between health systems, known as patient matching, plays a critical role in patient safety and quality of care, but has proven difficult to accomplish in the United States, the last developed country without a unique patient identifier. In the U.S., linking patient data is dependent on algorithms designed by researchers, vendors and others. Scientists have now developed an eight-point framework for evaluating the validity and performance of algorithms to match medical records to the correct patient.