What is the most helpful action if disclosure of a subject’s involvement in a study could be harmful?

The most helpful action in the context of potentially harmful disclosure of a subject's involvement in a study is to obtain a waiver of documentation of informed consent. This approach allows researchers to conduct their studies without having to maintain a formal record that links subjects to specific responses or participation, thus minimizing risks associated with identification.

When informed consent documentation is waived, participants are not required to sign a consent form that associates their name or identity with the study data, which helps safeguard their privacy. This measure is particularly crucial in sensitive research contexts where disclosure may lead to social, legal, or psychological harm.

In contrast, while encrypting data and removing identifying information are important measures for protecting data privacy, they may not adequately address the specific harm associated with revealing a subject's involvement if documentation linking them to that involvement still exists. Limiting the number of participants could reduce risk, but it might not effectively minimize the potential harm related to exposure. The focus here is on ensuring that participant identities remain confidential throughout the research process, making the waiver of documentation the most effective action in this scenario.