What is a matrix diagram?
A matrix diagram answers questions such as "which process steps affect which customer requirements?" or "which departments are involved in which problems?". By putting two lists at right angles and marking the strength of each relationship, it shows patterns that a list cannot: the steps that matter for many requirements, requirements with no owner, and items that are not connected to anything.
Matrix shapes
| Shape | Groups | Typical use |
|---|---|---|
| L-shaped | 2 | Requirements vs. process steps, problems vs. causes |
| T-shaped | 3 (one related to two) | Products vs. properties and vs. production methods |
| Y-shaped | 3 (each pair) | Requirements, functions and parts |
| X-shaped | 4 | Rarely used; complex portfolios |
Matrix diagram example
A distribution team relates five customer delivery requirements, weighted by importance, to six shipping process steps. Packing scores highest (87): it strongly affects whether products arrive undamaged and easy to open, and also the paperwork. Picking (62) and carrier handover (51) follow. Labeling has only medium links, and every requirement has at least one strong relationship. The team decides to focus process controls and audits on packing and picking.
Related tools
- Cause-and-effect matrix: score process inputs against weighted outputs.
- RACI matrix: a matrix of tasks against roles.
- Prioritization matrix: weight criteria and rank options.
How to use this Matrix Diagram tool
- Name the two lists. Name the matrix and what the rows and columns are, e.g. customer requirements and process steps.
- Add the rows. Click + below the rows to add each item, then click it to set its importance from 1 to 5.
- Add the columns. Click + next to the headers to add each column item.
- Rate the relationships. Click each cell to cycle ◎ strong, ○ medium, △ weak or blank.
- Read the result. The weighted scores and ranks under the matrix show which columns matter most; ⚠ marks rows without a strong relationship.
- Export. Export the matrix to PDF, PNG or Excel.
Frequently asked questions
What is a matrix diagram?
A matrix diagram shows the relationships between two or more groups of items, such as customer requirements and process steps, problems and departments, or tasks and people. The items of one group form the rows, the other the columns, and a symbol in each cell shows how strong the relationship is. It is one of the seven management and planning tools.
What do the symbols ◎ ○ △ mean?
They show the strength of the relationship: ◎ strong (usually scored 9), ○ medium (3) and △ weak (1). The 9-3-1 scale deliberately spreads the scores so that strong relationships dominate the totals. A blank cell means no relationship.
What are the types of matrix diagram?
The L-shaped matrix (two groups) is the most common and is what this tool draws. A T-shaped matrix relates one group to two others, a Y-shaped matrix relates three groups to each other in pairs, an X-shaped matrix four groups, and a C-shaped matrix three groups at once in three dimensions.
How are the weighted scores calculated?
Each row has an importance weight (1 to 5). For each column, multiply the strength in each cell by the weight of its row and add them up. The column with the highest weighted score has the most influence on the most important rows.
How is a matrix diagram related to the House of Quality?
The House of Quality (QFD) is built around an L-shaped matrix of customer requirements against technical characteristics, using the same 9-3-1 symbols and weights, with extra "rooms" for correlations, competitor ratings and targets.
What should I look for in the result?
Columns with high scores are where control and improvement matter most. Rows with no strong relationship are requirements nothing really addresses. Columns with no relationships may be unnecessary. Rows or columns full of strong symbols may need to be split.