Adverse Event: Any untoward or unfavorable medical occurrence in a human subject, including any abnormal sign (for example, abnormal physical exam or laboratory finding), symptom, or disease, temporally associated with the participants participation in the research, whether or not considered related to the participant’s participation in the research. Adverse events can be both physical and psychological harms and however they occur most commonly in the context of biomedical research, occasionally, they can occur in the context of social and behavioral research.

These can be anticipated or unanticipated.To determine whether an adverse event is an unanticipated problem, the following questions should be asked:

1. Is the adverse event unexpected?
   Unexpected (in terms of nature, severity, or frequency) the beginning of the research for this event to happen was unknown. (a) this event is not known in  the research procedures that are described in the project-related documents, such as the IRB-approved research project and informed consent document; and (b) the characteristics/type of the participant population being studied
2. Is the adverse event related or possibly related to participation in the research?
   Related or possibly related means there is a reasonable possibility that the incident, experience, or outcome may have been caused by the procedures involved in the research)
3. Does the adverse event suggest that the research places participants or others at a greater risk of harm than was previously known or recognized) than was previously known or recognized when the project was initially reviewed and approved by the IRB?

If the answer to all three questions is yes, then the adverse event is an unanticipated problem and must be reported to appropriate entities under the HHS regulations at 45 CFR 46.103(a) and 46.103(b)(5).