The New Seven QC Tools: Seven Tools and How to Choose
What Are the New Seven QC Tools?
The New Seven QC tools (N7) are seven management tools organized by Japanese quality experts: the affinity diagram (KJ method), relations diagram, tree diagram, matrix diagram, matrix data analysis, PDPC (Process Decision Program Chart) and arrow diagram (network chart). Unlike the old seven tools (check sheets, Pareto charts, cause-and-effect diagrams and others), which focus on data analysis, the new seven tools focus on organizing verbal information, clarifying complex relationships and building plans. They suit management-type problems and are the standard toolkit for managers and quality professionals dealing with non-numeric issues.
How to Choose Among the Seven
The tool gives selection guidance by scenario: use the affinity diagram to clarify vague problems by grouping brainstormed verbal data; the relations diagram to analyze causal and multi-factor relationships; the tree diagram to break goals and countermeasures into layers; the matrix diagram for multi-factor, multi-level correspondence; PDPC to guard against uncertainty and risk in a process; the arrow diagram for scheduling and progress management; and matrix data analysis for multivariate data. Each tool comes with a template and a worked example. The core selection principle is to look at the nature of the problem first and the tool's features second, since the tool is a means and solving the problem is the end.
Typical Applications
The new seven tools are commonly used in QC-circle activities, policy management, kaizen projects and ISO system planning: an affinity diagram organizes customer complaint information, a relations diagram analyzes the multiple causes behind complaints, a tree diagram breaks company policy down into departmental measures, and PDPC designs contingency plans for abnormal events in advance. They structure verbal information that is hard to articulate, making them a powerful aid in meetings and improvement activities. Combined with QC-circle activity, the new seven tools can run through the whole problem-solving process from topic selection, analysis, countermeasures to review.
How to Use Them (Step by Step)
Decide the type of problem to solve (organizing, analyzing, deploying, planning, scheduling), choose the tool from the selection guide, fill in the template with the team, summarize and discuss to reach a conclusion, and feed the output into follow-up actions (such as FMEA, 8D or project plans). Use them as a team rather than having one person do everything, keep the discussion records for review and promotion, and combine the new tools with the old seven tools (Pareto, cause-and-effect and other statistical tools) for a qualitative-then-quantitative approach.