National Statistical Organizations (NSOs) and other groups often use the term "for statistical purposes only" in communication with prospective respondents, data users and other stakeholders. This term also provides an important anchor for many NSO decisions on operations and ethics. Although public communication often omits a clear operational definition of this term, this paper will show that reviews of underlying laws and policies identify two predominant criteria: (1) production of statistical information about relatively large population aggregates, with the intention of creating a general public benefit; and (2) protection of the confidentiality of data collected about data subjects and a related prohibition against the use of information provided by or about data subjects for legal or regulatory action against those individuals or organizations. We then explore how this term exists, and is often interpreted, within a much broader landscape of legal requirements and of scientific and professional codes of practice, and provide a broader definition for consideration based on these and other ethical frameworks. This paper closes by highlighting several areas that warrant further discussion to better position NSOs to navigate these challenges in the future.