 Big data research is challenging for research ethics boards, often presenting what the computer ethicist James Moor would call “conceptual muddles”: the inability to properly conceptualize the ethical values and dilemmas at play in a new technological context. Subject privacy, for example, is typically protected within the context of research ethics through a combination of various tactics and practices, including engaging in data collection under controlled or anonymous environments, limiting the personal information gathered, scrubbing data to remove or obscure personally identifiable information, and using access restrictions and related data security methods to prevent unauthorized access and use of the research data itself. The nature and understanding of privacy become muddled, however, in the context of big data research, and as a result, ensuring it is respected and protected in this new domain becomes challenging.