One extremely important ethical issue is protection from harm.
Researchers must ensure that those taking part in their study are completely
protected from any kind of psychological or physical harm during and after the
study they conduct. Psychological harm may potentially be hard to identify in
participants as even they themselves may be unaware that they’ve been affected.
This is why it is important that researchers demonstrate their best efforts to
prevent this kind of harm (as well as physical harm) from occurring.