What defines human subjects according to federal regulations?

Human subjects are defined by federal regulations as living individuals from whom data is collected through interaction or intervention, or whose private information is obtained. This definition emphasizes the need for direct engagement with participants, whether through surveys, interviews, clinical trials, or other forms of data collection. Such interactions ensure that the collected data pertains to identifiable individuals, which is crucial for ethical considerations and protections under regulations like the Common Rule.

The other choices do not fulfill the criteria required by federal regulations. For instance, collecting de-identified data does not involve direct interaction with the living individuals themselves, hence does not qualify as working with human subjects as per the regulatory definition. Observations of public behavior without any interactions, as well as handling unidentified public information, do not involve data collection from identifiable individuals, which excludes them from being categorized as human subjects under the law. This highlights the importance of direct engagement and the collection of identifiable information in defining human subjects.