How to Analyze a Cause and Effect Diagram

Our previous blog, What is a Cause and Effect Diagram , introduced the technique and presented the cause and effect diagram below on why a car will not start.

This blog addresses how you analyze a cause and effect diagram. The first step is to examine each idea and determine the degree to which the idea is an actual cause of the problem. For example, how likely is no gas to be the reason the car won’t start. Is it very likely? Is it somewhat likely? Or is it...

What is a Cause and Effect (Fishbone) Diagram?

A cause and effect diagram is a tool that shows the relationship between a quality characteristic (effect) and possible sources of variation (causes). As shown below, the effect could be a problem that needs to be solved or the goal of the process. The effect would then be listed on the cause and effect diagram. The causes involve everything that might trigger the problem. Cause and effect diagrams are also called fishbone diagrams (because of their shape) and Ishikawa diagrams (because of their developer).

The cause and effect diagram is one of...

How Do I Analyze a Scatter Diagram?

Our previous blog ( What is a Scatter Diagram? ) included an example of overtime in a warehouse. You are a warehouse manager, and your boss is concerned about overtime. You think that overtime is caused by the work level – the more lines picked in the warehouse, the more overtime. You constructed a scatter diagram to see if that is true. That scatter diagram is shown below.

How do you analyze this scatter diagram? There are several things you can do. First, you can simply look at the scatter diagram...

What is a Scatter Diagram?

A scatter diagram shows the relationship between two variables. For example, you might want to compare the speed you drive with the time it takes you to get to work, or to compare the heights and weights of children, or to compare the steam usage in a plant to the outside temperature. This is what scatter diagrams do.

Suppose you are a warehouse manager. Overtime is a concern to you since it is something your boss watches closely. There is overtime every day. You have a theory that the overtime is simply caused by the work level – the number of lines that are picked each day in the...

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