Which tool is used to depict the relationship between specific categories of process inputs and the undesirable output?

• A. Problem framing model
• B. 3Ms and a P
• C. The Five-Why Method
• D. Fish Bone Diagram (i.e., cause and effect diagram)

Answer: (D)

This item tests your ability to recognize a visual tool that shows how different categories of inputs relate to an undesirable output. A Fish Bone Diagram, also known as a cause-and-effect diagram, is built for this purpose. It places the undesired output at the head of the “bone” and branches out into major cause categories—such as people, methods, machines, materials, environment, and measurements—with sub-causes flowing from each. This layout makes it easy to see where to focus investigation and which areas are contributing to the problem, guiding teams toward effective improvements.

Other tools don’t map input–output relationships in a single causal picture. A problem framing model helps define the problem and its scope but doesn’t graph the causes leading to the outcome. The 3Ms and a P provides categories to consider but doesn’t explicitly depict how those inputs connect to the problem in a diagram. The Five-Why Method is great for drilling down to root causes through iterative questioning, but it’s a linear approach rather than a multi-branch diagram that shows all major input categories and their links to the effect. So, the Fish Bone Diagram is the best fit for depicting the relationship between specific categories of process inputs and the undesirable output.