Which of the following is NOT considered PHI?

The correct answer is aggregate data on patient visits because this type of information does not contain any identifiers that can directly link it to an individual patient. Protected Health Information (PHI) is defined under HIPAA regulations as any information that can be used to identify a person and is related to their health, healthcare provision, or payment for healthcare. This includes specific details like a patient's treatment history, name, address, and insurance information—all of which can clearly identify an individual patient and their health information.

In contrast, aggregate data compiles information across multiple patients, presenting it in summary form without revealing any individual identities. For instance, a statistic indicating the number of patients treated for a specific condition over a period does not disclose any personal details about those patients. Therefore, it does not qualify as PHI, aligning well with HIPAA's intent to protect personal health data while allowing for broader healthcare analytics and research that do not compromise individual patient confidentiality.