Research ethics requires that researchers consider and attempt to mitigate all risks to participants taking part in research studies. Still, it is impossible to mitigate all risks at all times. Some studies may harm participants physically, some may harm participants psychologically or emotionally, and others may harm participants' reputations.
Medical testing on humans, for instance, is well regulated, but it can still be dangerous. Side effects of new drugs may cause adverse reactions in some participants. Alternatively, research in exercise science or kinesiology may require participants to push themselves to their physical limits. While this may not be harmful for more athletic participants, such tests could have negative health effects on participants who, knowingly or unknowingly, have health issues.
Research studies that may not have immediate physical effects can have damaging effects on a participants' psychological wellbeing. Interview questions designed to learn about the experiences of rape victims or those with post-traumatic stress disorder may trigger negative thoughts, anxiety, or panic.
Even when participants are comfortable talking to researchers about personal experiences, research has the potential to damage one's reputation. A studies on leadership styles in schools or business, for instance, might lead to questions about the way participants perceive their boss or principal. If they have negative things to say about their boss and the boss is able to identify them based on what was reported in the research, there may be retributive action levied against the employee.
Because of these potential issues, it is important that researchers follow a code of ethics, making sure that participants are informed about the studies for which they may volunteer. In general, participants should be kept anonymous, and any potentially identifying information should be kept to a minimum to protect participants. Researchers with access to this information should also follow any protocols set by institutional review boards.