ABSTRACT
The Management Oversight and Risk Tree (MORT) is an analytical procedure for determining causes and contributing factors (NRI-1 2002).
In MORT, accidents are defined as ‘‘unplanned events that produce harm or damage, that is, losses’’ (NRI-1 2002). Losses occur when a harmful agent comes into contact with a person or asset. This contact can occur either because of a failure of prevention or, as an unfortunate but acceptable outcome of a risk that has been properly assessed and acted-on (a so-called ‘‘assumed risk’’). MORT analysis always evaluates the ‘‘failure’’ route before considering the ‘‘assumed risk’’ hypothesis. In MORT analysis, most of the effort is directed at identifying problems in the control of a work/process and deficiencies in the protective barriers associated with it. These problems are then analysed for their origins in planning, design, policy, etc. In order to use MORT key episodes in the sequence of events should be identified first; each episode can be characterised as: {a} a vulnerable target exposed to; {b} an agent of harm in the; {c} absence of adequate barriers.
