Which diagram helps visually map cause-and-effect relationships to identify contributing factors in a problem?

• A. Flowchart
• B. Pareto chart
• C. Ishikawa (fishbone) diagram
• D. Scatter plot

Answer: (C)

Root-cause analysis benefits from a cause-and-effect map that visually links a problem to its potential causes. The diagram that does this best is the Ishikawa, or fishbone, diagram. It lays out a central spine for the problem and draws branches for major categories of causes—methods, machines, materials, manpower, measurement, environment, and management—so teams can brainstorm and organize possible factors in one view. This structure makes it easier to see which areas are contributing and where to target corrective actions. Flowcharts map steps in a process, Pareto charts prioritize issues by frequency or impact, and scatter plots explore relationships between two variables, while the fishbone diagram specifically shows the network of contributing factors that lead to the problem.