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.

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

Then add the secondary causes under each category:

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.