What is DMAIC in Six Sigma? Phases

  • Post last modified:18 March 2023
  • Reading time:13 mins read
  • Post category:Lean Six Sigma
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What is DMAIC in Six Sigma?

The acronym DMAIC stands for Define, Measure, Analyse, Improve, and Control. The DMAIC methodology is widely used across multiple industries and various lines of business to improve the effectiveness and efficiency of organizational processes. The DMAIC methodology is a powerful tool that can lead an organization to set and follow higher and stronger performance standards. When used skillfully, this methodology helps in resource streamlining and clarifying business goals.

Phases of DMAIC in Six Sigma

The five phases of the DMAIC methodology are described as follows:

Define Phase

This is the first phase of the DMAIC methodology. It focuses on a clear articulation of what the business problem is and a statement of project goals. The Define phase lists all details of potential resources and the scope and limitations of the project at hand. A high-level project timeline is also constructed in the Define phase.

A business document known as Project Charter contains this information. In this phase, managers are generally urged to write down what they know of current processes and seek clarifications on facts, if any. Setting objectives and forming the project team are also carried out in this phase.

Various activities carried out in the Define phase are as follows:

  • Defining the problem (Problem statement).
  • Documenting the Voice of the Customer (VOC).
  • Defining the Critical to Quality (CTQ) metrics that would determine the critical process outputs.
  • Establishing and outlining the borders of the project.
  • Eliciting stakeholder agreement on the parameters that will define the project.
  • Preparing the project scope and budget in alignment with the project goals.

Measure Phase

The main objective of this phase is to lay down objective baselines for current processes that would form the basis for project improvement. In this phase, the baseline data is collected and performance baselines are established. The baselines of this stage are compared with performance metrics at the end of the project (in the Analyse phase) to make an objective evaluation of the improvements resulting from the project.

The Six Sigma team, in consultation with the process owners, decides the parameters on which measurements have to be made. It is generally recommended that teams should invest adequate time and effort to assess the suitability of the proposed measurement systems. A good data collection plan is considered to be the most important aspect of the DMAIC process.

Various activities carried out in the Measure phase are as follows:

  • Concentrating on data collection relevant to the project scope.
  • Collecting reliable baseline data for making comparisons against future results.
  • Mapping interrelated business processes to outline areas of possible performance enhancements.

Analyse Phase

The primary objective of this phase is to determine, validate and select the root cause of the problem for elimination. Root cause analysis is a tool that aids in determining a large number of potential root causes also known as process inputs, X. A fishbone diagram is a tool for root cause analysis.

Using the fishbone diagram, Six Sigma professionals can determine the top four-five root causes by using techniques such as multi–voting or other consensus tools to validate the outcomes (established root causes). For substantiation, a data collection modality is planned and data collection is carried out that helps to establish contribution proportions for each identified root cause to the project metric, Y (process problem in measurable terms). The process is repeated for the identification of all valid root causes. The Six Sigma methodology often makes use of complex analysis tools.

Some activities that are carried out routinely in the Analyse phase are as follows:

  • Identifying the potential causes of the problem.

  • Prioritizing the root causes that form the key process inputs to be included in the Improve phase.

  • Determining the impact of process inputs (Xs) on process outputs (Ys) by data analysis. Here, Six Sigma professionals try to demonstrate the magnitude of the contribution of each root cause (X) to the project metric (Y). In addition, statistical tests are carried out using P–values. The test results are also accompanied by some other tools such as Pareto charts, histograms, and line plots.

  • Identifying the root cause of business inefficiencies. Sometimes analytic reports also include detailed process maps that demonstrate the site of root causes of the process and the reason for the occurrence. This activity helps to identify the root cause of business inefficiencies.

  • Identifying those areas in the process where maximum benefit can be achieved by the implementation of quality improvement initiatives.

Improve Phase

The main objective of this phase is to determine, identify, trial test, and implement a solution to the problem at hand. The solution may be implemented either in part or in entirety depending on the situation. In this phase, Six Sigma professionals try to identify creative solutions that may be used to eliminate the root causes to fix and prevent process problems from recurring.

There are many tools and techniques for this purpose, some of them being simple techniques such as brainstorming, random word, six thinking hats, etc. Sometimes complex analysis tools such as Design of Experiments (DOE) can also be used. Whatever may be the technique used, the focus remains on obvious solutions.

Some other objectives of the Improve phase are:

  • Identifying the easiest and simplest solutions.

  • Validating the proposed solutions using tools such as the Plan-Do-Check-Act (PDCA) cycle.

  • Identifying risks that are avoidable (based on the outcomes of the PDCA cycle) and can be associated with improvement initiatives by using tools such as the Failure Mode and Effect Analysis (FMEA).

  • Preparing and proposing a detailed implementation plan.

  • Deploying process improvement initiatives.

  • Undertaking pilot improvement activities and once successful they can be implemented organization-wide.

  • The Six Sigma team and process owners together devise methods that are used to overcome process deficiencies identified during the Analysis phase.

  • Recognizing improvement activities that need to be continued including activities such as feedback analysis and stakeholder participation.

Control Phase

The main objective of this phase is to sustain improvements made during the earlier phase of Six Sigma. Improvements made during the previous stage are monitored regularly to ensure sustainable and continued growth. This phase also includes the creation of a control plan and updating records as and when required.

A control chart is a useful tool during the control phase. The Six Sigma team uses it frequently to evaluate how stable are improvements over time. A control chart serves two purposes as follows:

  • Acts as a guide to be used for continuous monitoring of the improvised process.
  • Acts as a response plan for each measure being monitored in the case of process destabilization.

The most important objective of the Control phase is to develop metrics that help leaders monitor and document the continued success of the project. Some important considerations in Six Sigma are:

  • Six Sigma is an adaptive and continuous methodology.
  • The flexibility of this methodology allows adjustments to be made and to incorporate new changes (if required) after the completion of the initial DMAIC project cycle.

An optional but highly recommended step in the Six Sigma methodology is replicating processes and acknowledging the project team. Successful pilot processes should be considered for organization-wide replication. In addition, inter-departmental knowledge transfer should be carried out.

An acknowledgment of the team’s efforts goes a long way in increasing the morale of the team members. It not only helps in maximizing the effectiveness of the DMAIC cycle but also helps in creating buy-in for future improvement initiatives.

Sometimes, organizations require an extra (optional) phase in addition to the DMAIC cycle phases discussed above. This phase is called the Recognise phase with which the DMAIC cycle begins. This phase focuses on recognizing the right problem that needs to be addressed.

With the inclusion of this phase, the DMAIC methodology is renamed the RDMAIC methodology. A list of tools and techniques commonly used in various phases of the DMAIC cycle. You will study these tools in the forthcoming chapters.

PhaseTools and Techniques Used
DefineCustomer’s voice, also known as the Voice of the Customer (VOC)
Project charter
Value stream mapping
MeasureBusiness process mapping using flowcharts
Pareto chart
Process capability tools
AnalyseFailure Mode and Effects Analysis (FMEA)
Multivariate chart
Root cause analysis
ImproveDesign of Experiments (DOE)
Control plan
Statistical process control
Table: Tools and Techniques Used In the DMAIC Cycle
Article Source
  • Chowdhury, S. (2007). Design for Six Sigma. New York: Kaplan Publishing.
  • Bertels, T. (2003). Rath & Strong’s Six Sigma Leadership Handbook. Hoboken, N.J.: J. Wiley.

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