PDCA Cycle and MASP MethodologyRemember when we talked about Deming? He is known for the PDCA cycle (Plan – Plan / Do – Execute, / Check – Verify and Act – Act), disseminated and widely used by him:PDCA CycleImagine being in a medical office, where you only know that you are sick, but not the name of your disease. In the phase in which the doctor analyzes the symptoms, performs tests, and arrives at the root cause of the problem, we are facing the “Planning” phase (P – Plan, in English).When prescribing a treatment, the doctor is in the “Do or Execute” phase (D – Do, in English). When asking you to return for a future appointment, he is “Checking” (C – Check, in English) and taking corrective action, if necessary. Finally, when seeing the results, he “acts” (A – Act, in English), standardizing the treatment or ending it.The 4 phases of PDCA can be applied to solve real problems in our lives and problems that are part of every company.MASP captures these 4 phases of the PDCA methodology and breaks them into 9. It establishes a step-by-step process that begins with problem identification; its observation to define probable causes; continues with the application of testing and prioritization tools to determine the root cause; ending with the preparation of an action plan that addresses the cause and carries out control to verify the effectiveness of the action plan, for application of standardization or corrective action.Problem-solving methodology and analysisAlthough MASP or PDCA guides you with a concrete methodology for taking actions in order to solve a problem, they alone do not explain how you will identify the problem, much less which are the best solutions to solve it. PDCA by itself is just a flow of tasks to ensure that your problem will be solved. MASP seeks to go beyond PDCA by informing not only the flow of tasks, but that we should also use some tools to help us in the decision-making process.For example, we may be part of the marketing team for a children’s movie that unfortunately is not receiving the expected audience. How can we identify what the problem actually is? To help us, the great philosophers of Quality and MASP are clear: there are some basic quality tools that all company employees should know.ISHIKAWA (1993) classified statistical control techniques into 3 groups of increasing complexity. The first group consists of the 7 tools that require knowledge from everyone in the company and can be used in the analysis and resolution of 90% of quality problems. They are: Pareto Analysis, Cause and Effect Diagram, Histogram, Control Charts, Check Sheet, Scatter Plot and Flowchart.HistogramThe histogram is a statistical tool that measures the distribution of frequencies or intervals in relation to certain groups. For example, what is the distribution of the height of students in a classroom? Are there more students with 1.60 m or with 1.72 m? See how the histogram can show us interesting information. Think of the age distribution of two distinct groups: an indigenous tribe and a city in Japan. Most likely, there will be a greater concentration of older people in the Japanese city.HistogramThus, the histogram helps us explain data in a summarized way through a graph. We can quickly visualize the information when it is presented in graphical form.Scatter DiagramThe table below presents a sample containing the age, weight, and height of college students. Let’s analyze two correlation diagrams that deal with the same sample:Table with dataFirst, let’s check the correlation between the weight and height of the sample studied. Thus, we can build the following graph:Correlation between weight and heightit seems that, as height increases, weight also increases. In this way, we can prove that there is a positive correlation between the two variables.However, evaluating the variables age and weight, the following diagram does not present points grouped around a straight line. This means, in other words, that there is no correlation between the two variables. That is, there is no predictable relationship between weight and age.Correlation between weight and ageBelow, the possible types of scatter plots are summarized, also indicating whether there is correlation or not between the analyzed variables.Types of correlationPareto DiagramThis diagram is also known as the 80/20 rule, because its creator, Vilfrido Pareto, used it to explain that 80% of the wealth was in the hands of 20% of the population.Let’s think about the following case: imagine that you work in the quality assessment area of a hotel and that you are responsible for creating an action plan to improve your customers’ satisfaction.Your first step will certainly be to evaluate the list of customer complaints over the last few months. When looking at this list, you find that there are more than 100 different types of complaints. Which one would you start with? What would be a way to prioritize them? Which would carry more weight? The Pareto diagram can help you, because it orders the causes according to their frequencies, providing prioritization. It is composed of a bar chart that orders the frequencies of occurrences in descending order, allowing problem prioritization.To illustrate what we have just explained, we will use the same hotel example. See the table below and the category of the problems presented. For this example, we will limit the number of types (categories) of problems to just 10. The frequency column shows the number of times the problem was recorded:Problems presented at the hotelWith this table, we can construct the following Pareto diagram. Don’t worry yet about constructing the diagram. Let’s just analyze it together:Pareto diagram regarding the hotel problemsNote that the problems are arranged in descending order of frequency. Where would you start attacking them? With the employees’ friendliness? With the number of TV channels? Probably not. Note that the first three problems, when their frequencies are added together (cumulative frequencies), account for about 65% of the complaints. Thus, solving internet speed, menu variety, and the lack of daily room tidying would be the starting point.Notice that after solving the main problems, the following problems still remain within the Pareto relationship, since the 80-20 relationship between the second-place item and the rest still holds.FlowchartA flowchart is the representation of a process that uses graphic symbols to describe step by step the nature and flow of this process. The goal is to show, in a simple way, the flow of information and elements, highlighting the operational sequence that characterizes the work being carried out.The steps of the flowchart are presented through the use of geometric figures, which can be circles, triangles, rectangles, lines, or arrows, each symbol having an important meaning. Flowcharts should be used when we want to:• understand how a process works;• study a process in order to implement improvements;• communicate to other people how a process works;• document a process.As we mentioned a moment ago, a flowchart presents basic geometric shapes, each with a specific meaning. Below, we present these figures and their meanings:Basic flowchart figuresFlowchart exampleCause-and-Effect Diagram / Fishbone Diagram / Ishikawa DiagramOriginally proposed by engineer Kaoru Ishikawa in 1943, this diagram was improved in the following years. Also called fishbone or cause-and-effect diagram, it serves to help managers reflect on the causes and effects of a given problem and guide them toward its solution.Generally, these diagrams are made by work groups and involve all agents in the process under analysis. After identifying the problem or effect to be studied, a list of possible causes is made, and then the cause-and-effect diagram is created.The cause-and-effect diagram considers that problems are classified into six categories of causes, the famous 6M: method, raw material, labor, machines, measurement, and environment.MethodHere we group the problems related to the way work is carried out. The cause is not in the incorrect execution of an activity, but rather in the method used. In other words, the execution may be correct, but the method wrong.Raw materialThe causes possibly related to raw material are grouped here. For example, we need to verify whether the impact of a final nonconformity in a product may come from the use of a raw material outside specification. Or even whether the specification was made incorrectly.LaborHere we have causes related to employees’ actions. These actions may be related to the employee’s lack of technical preparation, failure to follow procedures, and even recklessness.MachinesCauses related to machine failures are grouped here. These failures may occur, for example, due to lack of maintenance. However, a large part of these failures is due to incorrect operation of the equipment. In this case, in addition to a cause in the “machines” category, a fault in the “labor” category should also be indicated.Measurement or measuresHere we are basically talking about measuring instruments and their calibration. When it comes to measurement, the following factors need to be considered for correct results: use of the correct measuring device, measurement method, calibration, and wear of the measuring device (when it must be replaced).EnvironmentThese are causes arising from the production environment, including temperature, humidity, noise disturbance, vibration, lighting, and internal pollution that may influence products or services.The DiagramBelow, we present a filled-in example of the diagram under study:Ishikawa DiagramControl chartIn this lesson, we will explain what a control chart is and what it is for, as well as its benefits. However, in the next lesson, when we address “statistical process control,” we will delve deeper into the topic, working on the construction of control charts.A control chart is a type of graph used to monitor a process, statistically determining a range called control limits. The upper range is called the upper control limit (UCL) and a lower line, the lower control limit (LCL). Both are represented in the graph below by the red color. The green line is the process mean. The objective is to verify, through the graph, whether the process is under control, that is, free of special causes.Control chartTo better understand this graph, let’s work with the following example: imagine a company that manufactures a part whose approval criterion is its diameter. For approval, the diameter of the part must be between 73.98 mm and 74.02 mm. Outside these values, the part is considered not approved, that is, rejected. With this in mind, you need to keep production within these specification limits.Control charts, by distinguishing common causes from special causes of variation and indicating whether the problem is local or deserves management attention, avoid frustrations and the cost of errors in problem-solving direction. To make this clearer, it is important to define special causes and common causes of variation in a monitored process:CommonSpecialDefinitionCumulative effect of uncontrollable causes, with little individual influence.Occasional failures that occur during the process, with great individual influenceExamplesVibrations, temperature, humidity, process systematic failures, among others.Variations in raw material, operating errors, machine adjustment inaccuracy, tool wear, among others.By improving the process, control charts generate:• increase in the percentage of products capable of satisfying customer requirements;• reduction of rework and scrap, thereby reducing manufacturing costs;• increase in the overall probability of acceptable products;• information for process improvementCheck SheetThe verification sheet presents a way to organize and present data in the form of a chart, table, or spreadsheet, facilitating data collection and analysis.Verification SheetConclusion about MASPMASP is the sum of the application of the PDCA cycle and quality tools. In other words, we are stating that, during the application of the nine stages of the PDCA cycle, the tools are used as a means of support in the search for a solution.PDCA + toolsThe figure above illustrates this proposed sum (PDCA + tools). We can see that, for example, in the identification phase, the tools “Pareto chart,” “control chart,” “verification sheet,” etc. were used. In the analysis phase, “brainstorming,” “5w and 2h,” and so on were used.Exercises(1) Would you like to improve the quality of CEFET-RJ or the course you are part of? How would you begin this application, which tools would you use?
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