Why It’s Necessary
A Cause and Effect Analysis is a method of analyzing an event or a problem, devised by Kaoru Ishikawa in the 1960s. The chart used to represent the information gathered in such an analysis is also known as a Ishikawa diagram. It represents the various causes related to an event in the form of arms leading toward an event. The entire structure is in the shape of a "fishbone," and hence a cause and effect diagram is also sometimes known as a Fishbone Diagram.
Its applications are so widespread in quality management that it is now considered one of the seven basic tools of quality management as listed below
- Cause and Effect Analysis
- Pareto Chart
- Check Sheet
- Scatter Plot
- Control Chart
- Flow Diagram
The following are the steps to be followed while conducting a cause and effect analysis
The event or the problem under consideration is written to the right.
An arrow is drawn which indicates the main causes leading to the problem. More arrows are drawn to the main arrow indicating various categories of causes.
Normally the various causes are categorized as follows:
The figure indicated to the right shows how a fishbone diagram normally looks. It indicates the event which is the "effect" and the various categories which are the "causes." The smaller arrows indicate sub-causes under each category. These sub-categories can branch out as far as necessary in an effort to try to determine the original cause for the eventual effect.
Various tools can be utilized to conduct a cause and effect analysis. Some of the methods are listed below.
Brainstorming – A group of people can brainstorm over the problem and come up with a comprehensive list which can then be further evaluated to determine if they are actual causes of the problem. If they are, they can be suitably represented on the cause and effect diagram.
Affinity Diagram – This can be used to group similar causes together under a common head once the brainstorming session is completed. It is normally used in conjunction with brainstorming.
5 Why Analysis – Sometimes, the causes which have been determined by brainstorming or through discussion may be a superficial indicator of an actual underlying problem. By digging further, one will be able to identify the root cause. Hence people follow a technique known as 5-Why Analysis in which one will ask the question "Why?" consecutively five times in order to determine the root cause of the problem.
You can make use of this Excel template to perform a Cause and Effect Analysis. This free download includes the file that produces the cause and effect diagram shown in the screen shot above. Just click on the link in this paragraph, download it as an Excel drawing, and modify it to suit your own project needs.