Causal and Consequence Analysis


One categorisation of techniques of hazard identification and risk analysis is into causal analysis and consequence analysis.

Causal analysis involves taking events (which may be system failures, hazards or accidents) and attempting to determine possible causes for those events, e.g., which component failures can lead to an accident. Fault Tree Analysis (FTA) is an example of a causal analysis technique.

Consequence analysis involves taking events (which may be component failures, system failures or hazards) and attempting to determine possible consequences of those events, e.g., which accidents may be caused by a particular component failure. Failure Modes and Effects Analysis (FMEA) is an example of a consequence analysis technique.

The selection of a technique can sometimes be made on the basis of whether causal analysis or consequence analysis is most appropriate at the current stage of the safety life cycle. For example, carrying out a Failure Modes and Effects Analysis (FMEA) at the component level is not feasible until the nature, and more specifically the failure modes, of those components are known.

Aside:

There is no clear delineation of causal and consequence analyses; some techniques, such as Hazard and Operability (HAZOP) studies, combine the two.

Warning:

Just because you are performing causal analysis is no reason to close your mind to new consequences, and vice versa.