Would a Unique Patient Identification Number Prevent Medical Errors?

As the US healthcare system moves toward a paperless, electronic medical records system, some have advocated for a universal patient identifier (UPI) system in which every medical patient is identified by the assigned number.
Proponents for such a system include Dr. Michael F. Collins, a board certified phsyician in internal medicine and chancellor of the University of Massachusetts Medical School, who writes in favor of such a plan in the Wall St. Journal.
Dr. Collins argues, “An ID system ‘could be the safest and most efficient way to manage health-care data.”
Yet, others worry about the privacy rights of patients. Dr. Deborah C. Peel writes in the same article, “Yes, assigning everyone a universal patient identifier, or UPI, would improve doctors’ ability to share information and make it easier for hospitals to differentiate one John Smith from another. But a universal health ID system would empower government and corporations to exploit the single biggest flaw in health-care technology today: Patients can’t control who sees, uses and sells their sensitive health data.” Dr. Peel is a psychiatrist and a health privacy expert in Texas.
While patient privacy is an important concern, patient safety is the highest concern and if, as Dr. Collins argues, a UPI would make healthcare safer for all involved, that is an avenue that should be explored.