High Quality Content by WIKIPEDIA articles! Conventional systems engineering methodologies do not provide guidance on how to reduce the risks of unexpected events. The term unexpected event has recently been coined, to stress the need to design systems to handle unexpected situations. This Wikipedia entry summarizes the contribution made by several scientists and methodologists (notably, Hollnagel , Casey, Reason, Dekker and Leveson), who specialize in human errors, to express their view that unexpected events should not be attributed to the person who happened to be there at the time of the mishap, and that they should not be regarded as force majeure. A better approach, which may help mitigating the risks of unexpected events, is by considering the human limited capability to coordinate with the system during the interaction .