Six Sigma Tools: What They Are and When to Use Each

What are Six Sigma tools?

Short answer

Six Sigma tools are the charts, analyses and structured checks a team uses in each phase of the DMAIC method to define a problem, measure it, find the cause of variation, test a fix and keep the gain. Common examples are SIPOC, process maps, Pareto charts, fishbone diagrams, FMEA and control charts.

Last updated 31 October 2026 · TeamAssurance

Which Six Sigma tools are used in each DMAIC phase?

Six Sigma projects follow DMAIC: Define, Measure, Analyse, Improve, Control. Each phase has its own set of tools, and most projects use only a handful.

Phase	Question it answers	Common tools
Define	What is the problem and who is it for?	Project charter, SIPOC, voice of the customer, critical-to-quality (CTQ) tree
Measure	How big is it today?	Process map, data collection plan, check sheet, measurement system analysis, baseline process capability
Analyse	Why does it happen?	Pareto chart, fishbone diagram, 5 whys, histogram, scatter plot, hypothesis test, regression
Improve	What fix works?	Brainstorming, pilot, FMEA, poka-yoke, design of experiments
Control	How do we hold the gain?	Control chart, control plan, standard work, audit schedule

What are the most important Six Sigma tools?

SIPOC puts suppliers, inputs, process steps, outputs and customers on one page, so the team agrees the scope first.
Pareto chart ranks causes by contribution, showing the few that matter most.
FMEA scores likelihood, severity and detectability of failure, so effort goes to the biggest risks.
Control chart plots a measure against calculated limits, separating normal variation from a real shift.
Process capability compares process variation with what the customer allows. Six sigma means about 3.4 defects per million opportunities.

How do you choose the right Six Sigma tool?

Start with the question, not the tool. Are you scoping, measuring, finding a cause, choosing a fix or holding a gain?
Match the tool to your data. Pareto and fishbone work with counts and team knowledge; hypothesis tests and capability need measured data.
Check the measurement first. If two people measure the same part differently, later analysis cannot be trusted.
Finish with a control tool. A fix with no control chart or standard work usually fades.

Six Sigma tools vs lean tools

Lean tools such as value stream mapping remove waste and delay. Six Sigma tools reduce variation and defects. Lean Six Sigma uses both; see process improvement methodologies.

Example

A packing line rejected about one carton in forty for a poorly sealed lid. The team scoped it with a SIPOC, tallied rejects by shift and machine, and a Pareto chart showed one machine caused most of them. A fishbone pointed at sealing temperature, a trial confirmed it, and a control chart on reject rate went on the line board so any drift would be seen the same day.

How TeamAssurance helps

In TeamAssurance, a Six Sigma project that follows the DMAIC steps is raised from the measures on the tier board and carried as an improvement with an owner, a due date and a link to the goal it supports. Reject rates and other measures sit on the board after the fix, so a drift shows up in the daily meeting, and the new method is kept as standard work. TeamAssurance does not replace statistical software for hypothesis tests or capability studies; it keeps the project and the follow-through in one place.

Frequently asked questions

What are the 7 basic quality tools?

The seven basic quality tools are the check sheet, Pareto chart, histogram, cause-and-effect (fishbone) diagram, scatter diagram, control chart and flowchart or stratification. They are simple, mostly chart-based, and sit behind most Six Sigma projects.

Which Six Sigma tool is used to find the root cause?

Teams usually combine a Pareto chart to find where the problem sits, a fishbone diagram or 5 whys to list likely causes, and a hypothesis test, regression or simple trial to confirm which cause is real.

Do you need software for Six Sigma tools?

Not for the basic ones. Process maps, check sheets, Pareto charts and fishbones can be drawn by hand or in a spreadsheet. Hypothesis tests, regression, design of experiments and capability studies are easier with statistical software.