The article linked at the top of this thread discusses the need for different identifiers in different information contexts (education, health, tax, etc.). Man

The article linked at the top of this thread discusses the need for different identifiers in different information contexts (education, health, tax, etc.). Many education institutions 20 years ago used SSNs as a unique identifier for students. On the first day of class, the only way to determine if a body present in a class was actually enrolled was to confirm SSN. Confirming identity in an education context is crucial in the first few weeks of class because being officially enrolled in a course affects student loans, work study, graduation paperwork, health insurance, etc. Additionally, many educational institutions have a policy that students not present for a class's first X meetings will be dropped from the course, a mechanism which allows students physically present to enroll in enrollment-capped courses (especially important for required courses). One of the most straightforward ways educators had of verifying that a body was in fact who that body said he or she was--was to ask for SSN because many educational institutions used SSNs as unique identifiers (but not necessarily verifiers). In other words, asking for verifying information enabled the educator to complete the institution's academic mission and to facilitate the educational needs of students. It is not the fault of educators that financial institutions also use SSNs as both means of identification and verification. As "clueless" as an educator might have been, he or she might be partially absolved for requesting PII in the context of educational bureaucracy. Granted, it would be better if each information context had unique identifiers that are not SSNs since SSNs are used by financial institutions. EDIT: readability, grammar, clarity.