What key factor influenced the IRB's determination that the researcher’s activity does not constitute research with human subjects?

The determination that the researcher’s activity does not constitute research with human subjects is primarily based on the fact that the data is publicly available and has no identifiers. When data is publicly available, it implies that it can be accessed by anyone without restrictions, suggesting a lower level of privacy concern. Additionally, having no identifiers means that it is impossible to trace the data back to specific individuals, thus protecting their anonymity. Together, these aspects indicate that the research does not engage with human subjects in a way that requires IRB oversight, as there is no risk to individuals’ privacy or confidentiality from the researcher's use of the data.

In contrast, options that involve interaction with subjects, data containing identifiers, or the researcher’s involvement in data collection would typically raise considerations regarding human subject protections. They imply a level of engagement and risk management that necessitates compliance with IRB guidelines. Thus, the absence of identifiers and the public nature of the data serve as crucial factors in determining that the research falls outside the scope of human subject research regulations.