Root cause quality assurance

QUALITY ASSURANCE - A comprehensive root cause methodology will often include a component to ensure that the method is being applied properly. 

Several quality assurance tests should be applied when using predefined trees. Firstly, predefined trees are designed to capture most root causes, but may not be comprehensive. A completeness check should be conducted on each branch of the tree to see if there are other root causes associated with the category of that branch that are not listed on the tree. 

Predefined trees are a convenient means of identifying root causes. Providing all of the causal factors have been determined, use of a comprehensive predefined tree should ensure that most, if not all, root causes are identified. Several quality assurance tests should help identify any remaining root causes. 

A timeline or sequence diagram is first developed, and then causal factors identified. Care should be taken to ensure that the checklist is not used too early. Be sure to determine what happened and how it happened before determining why it happened. Otherwise, the team will think that they have identified the right root cause(s), when in reality only one or two of several multiple causes have been determined. The causal factors are then applied one at a time to each page of the checklist(s) to identify relevant root causes. Those pages that are not relevant to the particular incident of interest are discarded. Similar quality assurance checks should be applied as those described for predefined trees. 

The theoretical basis of the different causal models becomes more obvious at the upper management level. MORT was the first comprehensive model to include organisational and individual factors at the top management level. At this level, it draws from quality assurance management principles. The SMORT and ILCI models have been influenced by this pioneering work and represent variations on the same theme. The concept of root causes originates from the MORT model. The checklist above shows the different items of a root-cause analysis. 

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