In this article, I want to introduce you to the DMAIC method, key aspect to the success of the Lean Six Sigma application. In previous posts, I have been able to explain in detail the essence of the methodology, as well as some benefits in becoming Green Belt and Black Belt. Let's learn how to perform?

Well, to implement Lean Six Sigma we need to keep in mind its great goal: to optimize the way that processes happen. We have a script to bring conviction- the DMAIC method that points us in the right direction.

Clearly, it is much easier to understand how we should conduct our projects, is not it?

Then, the sequence is divided into five execution steps: Define, Measure, Analyze, Improve and Control - hence the DMAIC method. The line of reasoning allows a technical and precise analysis of the whole problem, this avoids hasty conclusions and allows direct action in the root cause.

In addition to focusing on the financial outcome, the great secret of the DMAIC method is to unfold the planning step. Greater the dedication in this phase, shorter the implementation time and the probability of errors. This mentality is essential.

The importance of this planning moment can be seen in the fact that this method is divided into 5 steps, 3 of which are focused on this crucial phase of the project.

To be very clear, I will explain how each step happens - I also separated some questions that can guide you, as well as examples and concepts of the main tools used, phase by phase.


1. The DEFINITION step in the DMAIC method


The initial step could not be another: here, you define what you expect from the project. When we evaluate the history of the problem it is necessary to establish its processes clearly.

An important tip is to not let anxiety cause bad performance in this step. By going over this cycle, many frustrations may appear in the course of its development.

Running the DMAIC method may take a few months, as it is necessary to go through all the steps. So, to ensure the commitment of the team throughout the process, and also to formalize all the information defined in this step, it is very important to prepare the project contract, which is a tool that we will talk about below.

This contract will contain where the problem happens, which indicator you will use, who your project team will be, what schedule, which will be the database used. So your entire project team and your sponsors will be within the scope.

In order for you to find your goals more easily, some questions may guide you:


  • What is the problem to be solved in the project?

  • Who are the customers and suppliers affected by the process?

  • What goal do I want to achieve and what is the corresponding financial gain?

  • Which process is related to my problem?

It's time to act! The stages count on already established processes, this collaborates for an efficient work. There are some tools that can help your tasks.

To make it easier, I have separated some of these techniques - and their definitions - so that you already get used to these features. Check out:


  • Reasoning Map: is the document that records the driving rationale of the Lean Six Sigma project.

  • Customer Voice (definition of CTQs): A tool that describes the needs of internal or external customers about the delivered product / service.

  • Project Scope: is the project sizing. In scope, you define which elements will or will not be part of your plan.

  • SIPOC: diagram used to define the main process involved in the project in a macro way, making it easier to see the scope of the project.

  • Project Charter: document that formalizes the Lean Six Sigma project and signs an agreement between the team that runs it - the Belt and the company managers.

2. The MEASUREMENT step in the DMAIC method


In measuring, we know and observe how things are going at the moment. In this step, you need to raise the potential causes of the problem and analyze the database.

This will be done in two ways: a more quantitative and a more qualitative one.

On the quantitative path, we will pick up the database, select an indicator and study its behavior through some statistical tools that will be quoted later.

In the qualitative way, we will study the process more deeply, seek to discover where the problem defined in the previous step occurs. Let's map the information that is important and that will help us identify the potential causes of the project.

Your main objective in this stage should be to identify the potential causes, filtering the most important ones, that is, those that are priority, that generate more impact on the final results.

But attention: choose the proper numbers for analysis because the goals are already defined. The idea is to establish the size of the problem - there is no reason to analyze too much data if they do not lead you to your goal.

These questions can help you:


  • What is the current state of the process?

  • What are the sources of process variability?

  • Is the data reliable?

  • What is the behavior of the historical data collected?

The main tools of the MEASUREMENT phase are:


  • Process Map: is a more detailed graphic illustration of the process. It should document all its stages, including those that add value or not.

  • Fishbone: also known as Ishikawa Diagram, this tool allows for analysis of causes for a given effect through brainstorming.

  • Matrix Cause and Effect: is an array used to prioritize the inputs of a process according to the impact they cause on each of the customer's outputs or requirements.

  • Matrix Effort x Impact: complements the cause and effect matrix. This tool evaluates your input variables from the perspective of the variables effort for its analyzes and changes and impact on the output variable.

  • Descriptive statistics: analysis used to describe and summarize a database.

  • Histogram: Also known as Frequency Distribution Diagram, the histogram is a graphical representation of a set of data divided into uniform classes.

  • Boxplot: graphical representation constructed using the minimum and maximum value references, first and third quartile, median and outliers.

  • Pareto: statistical tool that assists in decision making, allowing the prioritization of problems, classifying them as little vital and many trivial.


3. The ANALYSIS step in the DMAIC method


In this step we analyze the measured data to allow us to know the current behavior.

We must identify the root causes - also called vital X's - that affect the process significantly and generate variability in the result of interest - also called the Y variable. So you can prove them with facts and data, using graphs, analysis statistics and qualitative tools.

This step is extremely important to the DMAIC method because it ensures that the cause chosen in the previous step that you prioritized, actually disturbs your process, compromising the outcome of your indicator. Answer these questions:


  • What are the root causes that we should tackle to improve the outcome of interest?

  • What are the root causes that we can identify and prove with the basic graphics? What about the statistical analysis?

  • What are the root causes that we can identify through a risk analysis?

The main tools of the ANALYSIS phase are:


  • FMEA (Failure Modes Analysis and its Effects): tool that aims to identify, hierarchize and prevent potential failures of a product or process;

  • Dispersion Diagram: used to prove the relationship between a cause and an effect;

  • Linear Regression: mathematical model that can explain the dependence between the input variables (x) and the output variable.

  • Hypothesis Testing: A statistical test used to determine if there is sufficient evidence in a data sample to state that a particular condition is true for the entire population.


4. The IMPROVE step in the DMAIC method


In this step, we will propose, prioritize, test and execute the solutions to the problem.

For each root cause studied and proven in the Analysis Phase, we identified an appropriate solution that will be implemented through an Action Plan. In addition, we verify the impact and results obtained with the implemented improvements.

As you can imagine, an action plan does not run from day to night. So this is probably the most time consuming step of the DMAIC method, taking 30-40 days from a Green Belt project, or 40-60 days on a Black Belt project.

During this phase of improvement, the Six Sigma team should present the new version of the process map, trying to eliminate everything that does not add value. To reach conclusions in an easier way, answer the questions:


  • What are the possible improvement actions?

  • Can all proposed improvements be made into solutions that can be implemented?

  • How to test the chosen solutions in order to guarantee the achievement of the goal without undesirable side effects?

  • How to measure financial results when the action plan is implemented?

The main tools of the IMPROVEMENT phase are:


  • Tree Diagram: tool used to map the paths to be covered in order to achieve a global goal, in the case of this step, to perform improvement actions.

  • Prioritization Matrix: matrix that assists in the prioritization of solutions raised based on cost, ease of implementation and positive impact on the cause.

  • Action plan - 5W2H: tool that deploys improvement actions in more tangible information.

  • 5S: quality program that aims to improve the work environment and productivity, based on five senses: sort, set in order, shine, standardize and sustain.

  • SMED: tool that aims to reduce the time of preparation or setup of equipment, and increasing its productive capacity.

  • Kaizen: is a methodology that allows to lower costs and improve productivity through the sense of continuous improvement.


5. The CONTROL step in the DMAIC method


Control is the last step of the DMAIC. At this point, it is important to monitor the results achieved after implementing the improvements and to establish controls that ensure the sustainability of the results.

For this, it can be found from the simplest techniques, like the elaboration of procedures and Check lists, to more complex techniques, like the use of devices to the proofs of errors and statistical control of processes.

It is very important to stress at this stage the question of the sustainability of what has been achieved. Many people think only of demonstrating and valuing the results obtained, and forget to establish means to maintain them.

Furthermore it is important to establish a Control Plan, so you will think of ways to ensure that these results are not lost.

Some effective choices are: conduct standardization training, review procedures, and define how results will be measured from that point on.

To see these results more clearly, the analysis of the returns and economic benefits achieved must also be carried out. To understand your results, answer the questions: Has the


  • The goal and financial results have been achieved?

  • What controls have been established to ensure the sustainability of the improvements made?

  • Who will be the manager of the process and how will it be monitored?

  • Is it necessary to create or update standards and procedures?

  • Who are the workers who will be trained?

The main tools of the CONTROL phase are:


  • Control Charts: it is a graphical tool for monitoring the variability and evaluation of process stability.

  • OCAP: is a tool used to identify chronic anomalies that must be attacked for process improvement.

  • Standard Operating Procedure (SOP): These are documents that record and standardize operations in companies.

  • Poka Yoke: they are error-proof devices that guarantee the controlled variability of a process.