Cause-and-Effect analysis

Cause and Effect analysis is a neat tool used in incident analysis.  Broadly speaking, it consists of breaking down the effect you want to avoid – the incident that happened – into causes and then into sub-causes.  Here I’m going to go through a brief description of how to do it.  It’s based on an incident at my lab, involving a failure to properly evacuate.

First put down the effect and add a long arrow down the middle of the page.  This will be your main axis of cause.

Get the main effect down first...
First put down the effect….



Now add the main causes as secondary arrows.  I find that these are usually under “Engineering”, “Manpower”, Management”, and “Equipment”.

…next add the primary causes…


Then add the secondary causes under each category:


…finally, add concrete, actually existing causes.


Personally, I find that this works really well in analyzing accidents, but I prefer the bowtie method when it comes to preventing the things from happening in the first place.





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