Infographic created by Sarah Anderson. Download a PDF.


Purdue’s Human Research Protection Program clarifies the differences between privacy, confidentiality and anonymity as they pertain to protection of individuals in research.

One of the key aspects of protecting individuals participating in research is making assurances to those participants regarding how their personal information will be protected. This includes protecting participants’ privacy, keeping information confidential, and/or allowing the participant to remain anonymous. Often times the terms privacy, confidentiality, and anonymity tend to be used interchangeably, when in reality these are different concepts that may require different types of participant protections. The following descriptions clarify the differences between these frequently misunderstood concepts and provide suggestions for how researchers might further protect study participants.

Privacy in research refers to protecting the individual’s right to control access to their participation in a study (i.e., extent, timing, circumstances).  When addressing privacy considerations, investigators must carefully consider how to approach an individual, the appropriate circumstances and setting where participants might be contacted, and where participant information will be collected. For example, a participant should not be asked for personal or sensitive information in a public setting. Instead, information should be collected in a private space where the discussion cannot be observed or overheard by others. Investigators should also limit the information collected to the information that is essential for research purposes, and only once informed consent has been obtained from the participant.

Confidentiality pertains to protecting the participant’s personally identifiable data. Confidentiality represents an agreement that is formed between the researcher and participant, via the informed consent process, that ensures the participant’s identity, personal information, responses, etc. will not be disclosed to anyone outside of the research team unless otherwise agreed upon. Participants should be informed that confidentiality cannot be guaranteed when identifiable information is being collected and notified of how their information will be stored during and after the study. Breach of confidentiality is a potential risk of participating in research. To protect participants’ confidentiality, you should encrypt computer-based files, store documents (i.e., signed consent forms) in a locked file cabinet and remove personal identifiers from study documents as soon as possible.

Finally, research that allows for anonymity does so by ensuring that no members of the research team collect any personal identifiers, direct or indirect, that would link responses to a specific individual. Data collected in person is not anonymous even if key codes are used instead of participant names or other identifiers. If a study is being conducted with a population where a combination of indirect identifiers (i.e., gender, ethnicity, age, class) are collected and may be used to identify a specific individual, then the study is not anonymous.

In summary, the protection of research participants should be a main focus for all researchers. When applying the concepts of privacy, confidentiality and anonymity in research, researchers must always consider not only what will be best for their research, but what is best for the participants who make the research possible. Each of these practices must be articulated in an IRB protocol application. Ensuring that participants’ rights are upheld to the highest standard is paramount in all research and should be at the forefront of all investigators minds while creating a study protocol.

For more information, see Tools for Protocol Development on our website.

Writers: Haley M. Holland, protocol analyst, Human Research Protection Program,; Jennifer S. Linvill, Ph.D., IRB administrator, Human Research Protection Program,