Quality Glossary Definition: DMAIC Show
Define, measure, analyze, improve, and control (DMAIC) is a data-driven quality strategy used to improve processes. The letters in the acronym represent the five phases that make up the process, including the tools to use to complete those phases shown in Figure 1. It is an integral part of a Six Sigma initiative, but in general can be implemented as a standalone quality improvement procedure or as part of other process improvement initiatives such as lean.  Figure 1: The DMAIC Methodology The DMAIC Process
DMAIC vs. DMADVDefine, Measure, Analyze, Design, and Verify (DMADV) is a data-driven quality strategy that focuses on the development of new products or services compared to existing ones. The DMADV method or approach is often used when implementing new strategies because of its basis in data, its ability to identify success early, and its method, which requires thorough analysis. Like DMAIC, it is an integral part of a Six Sigma quality initiative. DMAIC resourcesYou can also search articles, case studies, and publications for DMAIC resources. To DMAIC or Not To DMAIC? (Quality Progress) Identify when you need a structured method for problem solving. DMAIC Failure Modes (Six Sigma Forum Magazine) Read about actual experiences related to some of the key failure modes associated with DMAIC and effective countermeasures you can take. How to Scope DMAIC Projects (Quality Progress) Scoping is a vital part of the define phase and can have a long-term impact on a Six Sigma program’s ultimate success. Excerpted from The Certified Quality Engineer Handbook, ASQ Quality Press. What is the Mean, Mode & Median for the data in Column 1, Data Set A? a. Mean = 8.7, Mode = 8, Median = 7 An operational definition provides a clear acceptance standard. Which of the following are necessary parts of it? a. Voice of
customer, Test, Shipment Measure is the second phase of DMAIC. The main activity in the Measure phase is to define the baseline. While we have identified a project in the Define phase of DMAIC; let’s take the lessons learned from the first phase and also get the ‘real story’ behind the current state by gathering data and interpreting what the current process is
really capable of. “Life moves pretty fast. If you don’t stop and look around once in a while, you could miss it.” — Mathew Broderick as Ferris Bueller, Ferris Bueller’s Day Off In the Measure phase, Six Sigma team checks how the process is performing against the customer expectations and CTQs noticed in the Define
phase of DMAIC. Six Sigma is a systematic problem solving approach that is centered around defects elimination and variation reduction which leads to process improvement. One of the principal tools in Six Sigma is the use of the DMAIC methodology. (Also see DMAIC Overview). Particularly, DMAIC is a logical framework that helps you think through and plan improvements to a process in pursuit of achieving a Six Sigma level of excellence. There are five phases that are used in the DMAIC method. The purpose of the Measure phase is to understand the extent of the problem with the help of data. In other words, measure the process performance in its current state in order to understand the problem. The Measure phase is approximately 2 to 3 weeks process based on the project inputs. In particular, all the relevant stakeholders’ involvement is key in getting the quality data. The measure phase is all about the baseline of the current process, data collection, validating the measurement system, and also determining the process capability. There are multiple tools and concepts available in the Measure phase of six sigma. Process Definition & Basic ToolsProcess map: Process map is a tool that graphically shows the inputs, actions, and also outputs of a process in a clear, step-by-step map of the process. The process map illustrates the relationship between inputs (X) and outputs (Y). Create a process map of all the activities required to convert raw materials into output (Y) and then identify the critical to quality (CTQs) factors in the process. Process map helps to identify the inefficiencies or wastes in the process. This also helps to determine the critical steps to collect the data. Value stream mapping: Value stream mapping provides a visual representation of the flow of materials and information throughout the organization. Value stream mapping constitutes all the value added as well as non- added values required to make the product. It consists of the process flows starting from the raw materials to make the product finally available in the hands of the customers. Spaghetti Diagram: Spaghetti diagram also known as Spaghetti chart represents the basic flow of people, products, and process documents or papers. Cause and Effect Matrix: Cause and effect matrix establishes the correlation between process input variables to the customer’s outputs during root cause analysis. Data CollectionIn fact, the measure phase is all about collecting as much data as possible to get the actual picture of the problem. Hence, the team has to ensure the measurement process for data collection is accurate and precise. Data TypesData is a set of values of qualitative or quantitative variables. It may be numbers, measurements, observations or even just descriptions of things. Below are the types of Quantitative Data
Coding DataSometimes it is more efficient to code data by adding, subtracting, multiplying or dividing by a factor. Types of Data Coding
Data Collection PlanData collection plan is a useful tool to focus your data collection efforts on. This directed approach helps to avoid locating & measuring data just for the sake of doing so.
Plan for and begin collecting data
Measurement System AnalysisMeasurement System Analysis (MSA) is an experimental and mathematical method of determining how much the variation within the measurement process contributes to overall process variability. Accuracy: It is a difference between the true average and observed average. If the average value differs from the true average, then the system is not accurate. This is an indication of an inaccurate system. Precision: Precision refers to how close the data points falls in relation to each other. In other words, a high-precision process will have little variance between the individual measurement points. Gage R&RThe Gage Repeatability and Reproducibility is a method to assess the measurement system’s repeatability and reproducibility. Furthermore, Gage R&R measures the amount of variability in measurements caused by the measurement system itself. Gage R&R focuses on two key aspects of measurement: Repeatability: Repeatability is the variation between successive measurements of the same part, same characteristic, by the same person using the same gage. Reproducibility: Reproducibility is the difference in the average of the measurements made by different people using the same instrument when measuring the identical characteristic on the same part. Six Sigma StatisticsBasic six sigma statistics is the foundation for six sigma projects. It allows us to numerically describe the data that characterizes the process Xs and Ys. Statistics is a science of gathering, classifying, arranging, analyzing, interpreting, and presenting the numerical data, to make inferences about the population from the sample drawn. There are basically two categories. Analytical(aka Inferential statistics) and Descriptive (aka Enumerative statistics). Inferential statistics: It is used to determine whether a particular sample or test outcome is representative of the population from the sample was originally drawn. Descriptive statistics: A descriptive statistic is basically organizing and summarizing the data using numbers and graphs. Descriptive statics is to describes the characteristics of the sample or population.
The shape of data distribution depicted by its number of peaks and symmetry possession, skewness, or uniformity. Skewness is a measure of the lack of symmetry. In other words, skewness is the measure of how much the probability distribution of a random variable deviates from the Normal Distribution. Data Organization / Data Display / Data PatternsThe graphical analysis creates pictures of the data, which will help to understand the patterns and also the correlation between process parameters. Graphical analysis is the starting point for any problem-solving method. Hence select the right tool to identify the data patterns and to display the data.
Basic Probability & Hypothesis testsBasic Six Sigma Probability terms like independence, mutually exclusive, compound events, and more are the necessary foundations for statistical analysis. Additive law: Additive law is the probability of the union of two events. There are two scenarios in additive law
Multiplication law: It is a method to find the probability of events occurring at the same time. There are two scenarios in multiplication law
Compound Event: It is an event that has more than one possible outcome of an experiment. In other words, compound events are formed by a composition of two or more events. Independent Event: Events can be independent events when the outcome of the one event does not influence another event’s outcome. Hypothesis TestingHypothesis testing is a key procedure in inferential statistics used to make statistical decisions using experimental data. It is basically an assumption that we make about the population parameter. When using hypothesis testing, we create:
Determine the process capabilityProcess Capability Analysis tells us how well a process meets a set of specification limits based on a sample of data taken from a process. The process capability study helps to establish the process baseline and measure the future state performance. Revisit the operational definitions and specify what are defects and which are opportunities. Calculate the baseline process sigmaThe value in making a sigma calculation is that it abstracts your level of quality enough so that you can compare levels of quality across different fields (and different distributions.) In other words, the sigma value (or even DPMO) is a universal metric, that can help yourself with the industry benchmark / competitors. Baseline Sigma for discrete dataCalculate the process capability is through the number of defects per opportunity. The acceptable number to achieve six sigma is 3.4 Defects Per Million Opportunities (DPMO).
Baseline Sigma for Continuous dataProcess Capability is the determination of the adequacy of the process with respect to the customer needs. Process capability compares the output of an in-control process to the specification limits. Cp and Cpk are considered short-term potential capability measures for a process. Cpk is a measure to show how many standard deviations the specification limits are from the center of the process.
Six Sigma derives from the normal or bell curve in statistics, where each interval indicates one sigma or one standard deviation. Moreover, Sigma is a statistical term that refers to the standard deviation of a process about its mean. In a normally distributed process, 99.73% of measurement will fall within ±3σ and 99.99932% will fall within ±4.5σ. Measure Phase of DMAIC Deliverables
Measure Phase of DMAIC VideosAt which stage of a DMAIC project is a detailed process map flow typically created?The most basic of process maps are created in the earliest phases of the Six Sigma process, particularly in the Define phase. Here, the process flow map is created to get an understanding of the process to be improved, and to ensure that all team members have a solid grasp on the steps involved in the process.
In which phase or phases should a Lean Six Sigma team be creating process maps?Process mapping enters at the very first stage. Anyone involved with optimizing processes or eliminating defects needs to first define the process and understand it completely. A Six Sigma process map outlines the process graphically step by step to make understanding faster and easier.
What is a process map in DMAIC?The process map is a tool that graphically shows the inputs, actions and outputs of a process in a clear, step-by-step map of the process. This is tollgate # 3 of Define in the DMAIC. The purpose of process mapping is to help team members and others within the process to understand the process.
In which stage of the Lean Six Sigma DMAIC process is a charter established a Define B measure C analyze D improve E control?Define is the first phase of the Lean Six Sigma improvement process. During this phase the project team drafts a Project Charter, plots a high-level map of the process and clarifies the needs of the process customers.
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