Pareto Analysis
A data-prioritization method for selecting the recurring category with the greatest measured impact before deeper investigation.
Quality knowledge center
Quality Problem Solving
Quality problem solving is the structured process of defining a quality issue, prioritizing what to investigate, examining possible causes, verifying the actual causal mechanism and implementing actions that prevent recurrence.
Choose a method that fits the investigation
Each method helps a team examine a different problem structure. None automatically proves root cause; evidence, observation, records, testing or controlled verification are still required.
Fishbone / Ishikawa
A broad way to organize potential causes across several cause families.
5 Why
A focused way to examine one causal chain through iterative questioning.
Fault Tree Analysis
A top-down way to examine event paths and AND/OR combinations.
8D
A structured cross-functional methodology covering containment, root-cause verification, corrective action, prevention and closure.
Which problem-solving method should you use?
| Situation | Useful starting method |
|---|---|
| Recurring categories with measured frequency, cost, downtime or quantity | Pareto Analysis |
| One focused causal chain | 5 Why |
| Several possible cause families | Fishbone Diagram |
| Interacting events with AND/OR relationships | Fault Tree Analysis |
| Full cross-functional complaint and corrective-action process | 8D |
Evidence turns a possibility into a verified finding
Methods organize questions and causal hypotheses. They do not by themselves prove the cause of a failure. Teams should verify the predicted causal mechanism through appropriate records, observation, samples, testing or controlled reproduction before they define corrective action.
Other quality problem-solving approaches
PDCA: a repeatable plan-do-check-act learning cycle for controlled improvement.
DMAIC: a data-driven Define, Measure, Analyze, Improve and Control framework.
A3 Problem Solving: a concise visual format for framing, analysis, action and follow-up.
Is / Is Not Analysis: a fact-based way to define where, when and how a problem occurs—and where it does not.
Learn, build, then manage the investigation
Use these guides to learn the methods and the free builders to perform an analysis. For issues needing containment, team ownership, verified corrective action, prevention and closure, move into a structured 8D investigation.
Use the 8D workspace