HKSM

A visual root-cause analysis tool that shows a stated problem at the head and organizes possible causes along branching 'bones' by category, allowing the team to drill down into sub-causes; also known as a cause and effect diagram.

Key Points

• Clarifies the relationship between an effect (problem) and potential causes grouped by category.
• Built through facilitated brainstorming; teams ask "why" repeatedly to add deeper sub-causes.
• Typical categories include Methods, People, Materials, Equipment/Technology, Environment, and Measurement (adapt as needed).
• Supports problem exploration; findings should be validated with data before selecting corrective actions.

Example

During Control Quality on a software project, the team faces recurring login failures. The project manager leads a fishbone (cause and effect) session. Categories include People, Process, Tools, Environment, and Requirements. The team maps sub-causes such as ambiguous acceptance criteria, flaky test environment, missing input validation, and skipped peer reviews. These insights guide targeted experiments and fixes.

PMP Example Question

During a quality review, a project team wants to structure and brainstorm potential reasons for a persistent defect before running experiments. Which tool should the project manager use?

1. Pareto chart
2. Fishbone diagram (cause and effect diagram)
3. Control chart
4. Scatter diagram

Correct Answer: B — Fishbone diagram (cause and effect diagram)

Explanation: A fishbone diagram is used to brainstorm and organize possible causes of a problem by category before validating them with data.