What are the Critical Six Sigma Tools?

Six Sigma tools are used to drive quality improvements, strategically and systematically within a company, which is focused around the DMAIC model. Most of these tools used are nothing more than quality methods that have been around for years and some for centuries.

They are used under the DMAIC roadmap, to bring together years of various process improvement techniques and data analysis, into a structured step by step format, with the aim of finding and eliminating root causes to process problems.

The result – a more robust process that consistently achieves a high standard of output – one which is capable and in control!

Six Sigma Tools and steps

The following tools are not an exhaustive list, but merely highlight the most utilised six sigma tools during each phase of a project.

D – Define Phase: Define the problem, project goals, scope of the project and customer (internal and external) deliverables. Get as much background information to the problem to strategically support the project.

Typical tools to use:

• Project Charter
• Value Stream Mapping
• Process Flowchart
• SIPOC Diagram
• FMEA
• Understanding CTQs
• Stakeholder Analysis
• Cause & Effect Matrix
• DMAIC Work Breakdown Structure
• Voice of the Customer

M – Measure Phase: Measure the process to determine current baseline performance. Understand what the problem is and in what conditions it exists. At this stage, initial process measurement can be conducted, to understand the voice of the current process and begin developing ‘Y=f(x) relationship.’

Typical tools to use:

• Process Flowchart
• Cause & Effect Matrix
• FMEA
• Data Collection Plan/Example
• Benchmarking
• Measurement System Analysis
• Gage R&R
• Voice of the Customer Gathering
• Process Sigma Calculation

A – Analyze Phase: Analyse the data to understand the Voice of the Customer to evaluate why the problem is occurring and what the potential root cause(s) of the defects are. At this stage, the focus is to narrow down the many ‘X’s’ (or causes) to the vital few.

Typical tools to use:

• Histogram
• Pareto Chart
• Time Series/Run Chart
• Scatter Plot
• Regression Analysis
• Cause and Effect/Fishbone Diagram
• 5 Whys
• Process Map Review and Analysis
• Statistical Analysis
• Hypothesis Testing (Continuous and Discrete)
• Non-Normal Data Analysis

I – Improve Phase: Improve the process by eliminating defects and the root causes to the problem. Performing design of experiments, and possible solutions, verifying whether these solutions work, and eradicating the root causes.

Typical tools to use:

• Brainstorming
• Mistake Proofing
• Design of Experiments
• House of Quality
• Failure Modes and Effects Analysis (FMEA)
• Simulation Software

C – Control Phase: Create the new standard process, which captures the new way of working, and control future process performance. Process analysis is critical here, to understand the new process capability and contro, ensuring that the new process is indeed capable and in control.

Closing the project out also means that project cost savings should be calculated and verified and all transfer plans/processes created.

Lastly, celebrate the success and communicate to the business!

Typical tools to use:

• Process Sigma Calculation
• Control Charts (Variable and Attribute)
• Cost Savings Calculations
• Control Plan

As you may have seen, some six sigma tools are used throughout the project, like control plans, cause and effect diagrams, FMEA, process flow charts and others. That is because new ideas may emerge at anytime during the project, factors that were previously thought of as being a big impact to the process may eventually be proved otherwise.

At each stage, returning to previous steps or methods, helps close off all possibilities and also allows the team to track the history of the project in a concise way.