A Matrix Diagram shows relationships between two or more sets of factors so teams can compare links, strength, ownership, priorities, or requirements systematically.
Definition
A Matrix Diagram is a planning and analysis tool that displays relationships between items such as requirements, causes, tasks, functions, customers, controls, or owners. The matrix format helps teams see where relationships are strong, weak, missing, or duplicated.
It is one of the new seven management and planning tools and is useful when lists alone do not show cross-functional relationships.
History
Matrix diagrams became common in quality planning and management tools as teams needed practical ways to connect customer requirements, process factors, responsibilities, and countermeasures. QFD and prioritization methods use similar matrix logic.
When to Use
Use a Matrix Diagram when mapping relationships between CTQs and process inputs, actions and owners, failure modes and controls, skills and people, customers and requirements, or causes and effects.
Step-by-Step
- Define the relationship question.
- List one item set across rows and another across columns.
- Choose a relationship scale or symbol set.
- Evaluate each intersection with evidence or team knowledge.
- Look for strong relationships, gaps, clusters, and overload.
- Use the pattern to prioritize action or clarify ownership.
- Review with affected stakeholders.
Examples
- Training: A skill matrix maps employees to required job skills.
- Quality: CTQs are connected to process inputs.
- Project work: Countermeasures are mapped to owners and due dates.
Common Pitfalls
- Unclear relationship criteria.
- Filling the matrix with guesses only.
- Too many rows and columns.
- No action after identifying gaps.
- Using equal weights where importance differs.
- Letting one function define relationships alone.