My Reading on ASQ CQA HB Part V Part 1 small

Charlie Chong/ Fion Zhang
Part VA
Cause-and-Effect Diagrams
The cause-and-effect diagram (C-E diagram) is a visual method for analyzing causal factors for a given effect in
order to determine their relationship. The C-E diagram, one of the most widely used quality tools, is also called
an Ishikawa diagram (after its inventor) or a fishbone diagram (because of its shape). Basic characteristics of
the C-E diagram include the following:
• It represents the factors that might contribute to an observed condition or effect
• It clearly shows interrelationships among possible causal factors
• The interrelationships shown are usually based on known data
C-E diagrams are an effective way to generate and organize the causes of observed events or conditions since
they display causal information in a structured way. C-E diagrams consist of a description of the effect written in
the head of the fish and the causes of the effect identified in the major bones of the body.
These main branches typically include four or more of the following six influences but may be specifically
tailored as needed:
1. People (worker)
2. Equipment (machine)
3. Method
4. Material
5. Environment
6. Measurement
Figure 18.2 is a C-E diagram that identifies all the program elements that should be in place to prevent design
output errors.