Privacy relates to the method for collecting data; in other words, the study's location, tools, and planned interactions affect your ability to maintain your participant's privacy.
When you obtain IRB approval for a study, you will need to explain how you will respect the participant’s privacy. Sometimes researchers are confused about how to determine what information is private. A good question to ask is, “Would a reasonable member of the population being studied consider the information to be private?” For example, covert observation of public behavior (e.g., studying pedestrians on a crowded street) would probably not be considered an invasion of privacy, while covert observation of behavior in a person’s home would. Also, behavior that occurs in public places may not be public behavior if the individuals involved have a reasonable expectation of privacy (e.g., if it occurs in a public restroom).
With the exception of some observational studies, most research in the social and behavioral sciences involves private behaviors, and protecting the privacy of your participants means giving them control over the information that they share with you. This means asking permission and obtaining consent to conduct any study procedures with individual participants, allowing them to refuse to answer any questions or complete any study tasks that they find objectionable, and ensuring that the study is run in a private place. For example, if you are asking sensitive questions, you may want to consider finding a secluded room for interviewing participants and/or using white noise machines to reduce the chance that sensitive information may be overheard. In some cases where a potential invasion of privacy may exist in situations because consent is not possible (e.g., reviewing academic or medical records for epidemiological studies) measures are still taken to protect the privacy of participants. Using anonymous data and/or data stripped of identifiers through appropriate methods protects participants even if their data are accessed without a consent form.
An important issue related to the privacy of your research participants is the privacy of “secondary subjects.” These people are individuals who are not participating in the research themselves, but about whom information may be gathered. For example, participants may be asked to complete questionnaires asking about health information, social history, or lifestyle habits of individual family members. In this situation, the family members would be secondary subjects, because private, individually identifiable information about them is being sought by an investigator. Since the federal definition of human subjects includes these individuals, you are required to protect their privacy, just as you would protect the privacy of your primary subjects. In research that involves only minimal risk, the IRB may waive the requirement for secondary subjects to provide informed consent, but otherwise consent of secondary subjects may be required as well unless a waiver of consent is justifiable.