Six Sigma Green Belt Certification Practice Exam

Which of the following is a common tool for root cause analysis?

1. Flow chart

2. Fishbone diagram

3. Histogram

4. Control chart

The correct answer is: Fishbone diagram

The fishbone diagram, also known as the Ishikawa or cause-and-effect diagram, is widely recognized as a powerful tool for root cause analysis. This visual representation assists teams in identifying, organizing, and categorizing potential causes of a problem or issue. The diagram resembles a fish's skeleton, with the "head" representing the problem and the "bones" branching out to capture various categories of potential causes, such as people, processes, methods, materials, environment, and measurement. By using a fishbone diagram, teams can systematically explore various factors that might contribute to an issue, fostering a comprehensive understanding that goes beyond surface-level symptoms. This leads to more effective problem-solving and enables the development of targeted solutions that address the root causes rather than just the effects. In contrast, while flow charts can help visualize processes and identify areas for improvement, they do not specifically focus on root causes. Histograms are useful for displaying the distribution of data points, and control charts monitor process stability over time, but neither directly aids in identifying underlying causes of problems.