Seven quality tools
PART ONE: SEVEN QUALITY TOOLS
INTRODUCTION
For the reason of human factor and human reliability, it is inevitable that there could be occurred some kind of faults and errors even in well planned and technically equipped organizations and systems. The errors or unplanned risks that might be happened during the project, can lead the customer to have negative opinion about the management team. Also some faults and risks might not being able to fix or might be too expensive to overcome it. Therefore a well prepared quality management plan is essential for an organization in order to ensure that the management plan that the project team works on, meet the customer satisfaction and their needs. At this stage Ishikawa’s seven quality tools are quite helpful to determine, identify and evaluate the problems, their causes and suggestions for a continuous improvement process. These tools can be listed as; Histogram, Flow Chart, Scatter Diagram, Pareto Chart, Cause and Effect Diagram, Check Sheet and Control Chart.
1. HISTOGRAM
1.1 Purpose of Histogram
Histogram is used in order to define the variation and frequency of occurrence of a set of data in a graphical and numerical form.
1.2 Description
In most of the visual presentations, frequency distribution is used, and each of them is made in order to indicate how often that particular data occurs for in certain of time. And the most common way to show the frequency of occurrence is one of the quality tools called histogram. They may look like bar charts, but there are differs in some ways.
Histogram is a powerful tool in terms of showing the all data set in one diagram. It is helpful, when it is needed to show the comparison of one data to another. They are the graphical way of indication and provide to investigate and evaluate the data visually. It is invented by French statistician A.M Guerry. As a distinct from the Pareto Chart, in histogram, only the frequency of occurrence of one type of property of the product is shown. The particular property of the product that leads us to use histogram must be numerical and variable. The following figure 1 is given as an example. Here, one particular property of the products, the number of defective numbers in the next 1000 product and their probability of occurrence are shown as numerically. As you see from the figure, a pile of defective number is in the middle of the distribution. It is shown like a bell shaped curve which is usually called normal distribution.
We usually use a Histogram when;
- The data we use to visualize is numerical.
- There is a need to assess if the process is likely to meet the customer’s requirement.
- There is a need to identify the shape of the distribution that the histogram will show, for that particular data.
- Making a comparison of the outputs of more than one process, to assess if they are differing from each other or not.
When making a histogram with the purposes defined above, one should pay attention some points such as;
- The survey data should be variable.
- The observed data should place the X axis, while frequency should be place Y axis.
- In one histogram only one particular quality characteristic is considered, and observed data values regarding with this characteristic are placed on X axis.
- The column intervals should be same with one another.
- In order to reach the more accurate distribution, it should be paid attention to insert no less than 50 data points.
1.3 Construction of Histogram
While making a Histogram, there are some steps which should be followed. These are shown as follows:
- In order to reach more verifiable results, at least 50 data points should be gathered.
- Finding the difference between the highest and lowest data points, this is called as Range.
- Collected data points should be divided on to X axis according to their number. For example if we have below 50 data points, X axis should be divided into 5 to 7 intervals. The same, for 50 to 100 data points, axis should be divided into 8-10 intervals. For over 250 data points, number of intervals must be between 15 and 20. Determining the number of classes is the crucial step, since during the interpretation of the variation in the data set, it will show the effectiveness of the histogram.
- Each size of interval must be calculated by the following formula ;
- Size of Interval = Range/ Number of Classes
- By using the smallest and largest data points, the boundary of the histogram should be defined.
- Before the last step there is needed to make the calculation of frequency of each class.
- Final step is drawing the Histogram and plotting the related data.
1.4 Conclusion
Histogram is a useful tool to identify and make an interpretation for the variation that is faced in a set of data. Anything we need to show or point out, we can do it by the quality tool of histogram in a simple and clear way. But it is important to always consider that, histogram cannot give solutions to the problems, but they can shed some lights on the improvement processes.
2. FLOW CHARTS
2.1 Purpose of Flow Charts
Flow Charts give a visual explanation of the progression of activities which are needed to complete a task. The high level flow charts help people who use them, to understand complicated processes without details which cause confusion. The detailed flow charts help people who use them, to analyze their processes to improve the efficiency and to optimize.
Also people who will involved in constructing process of flow chart, start to understand the process better. Since they are involved in, they start to be more interested to the improvement of quality and process. They start to determine the parts to improve the process. They also start to understand how all the people and all the process involved and fit into the overall business.
2.2 Description of Flow Chart
Flow charts are visual charts which show processes by breaking down them into activities. Also they show how these activities related to each other from start to finish.
To understand a process, making a flow chart is the first step. Whether this process is a managerial or production one, these charts provide a visual explanation of the steps which are needed to complete the tasks. When we look at the flow chart, we can see how this process and the steps of this process are included in and fit into the overall business.
Flow charts can be prepared in many types. Pictures, symbols or just circles and squares can be used to draw a flow chart. Also these charts can show a process or just a part of a process or many processes together. There is not one way to draw a flow chart and also there is no wrong ways to draw a flow chart. The scale of how well a flow chart is, should be parallel with how well the people who draw and use it, understand it.
2.3 Construction of Flow Charts
While preparing a flow chart, the people who will be involved in, should be identified correctly. These people should be the ones who practically perform the process and stakeholders of the process.
Since to construct a flow chart takes more time then expected, enough time should be given out to the team members to complete their work.
In the construction process of flow chart, the crucial step is asking questions. Here are the examples of questions that will help to construct a flow chart:
- Which thing will happen first? (defining start point)
- Which will happen next? (listing major steps in order)
- To where do the outputs of this process go? (defining the direction)
- From where do the inputs of this process come? (defining the direction)
- How do the inputs reach the process?
- Which thing will happen last? (defining stop point)
After defining the data to construct a flow chart, standardized graphical symbols are used to document the process. Then the results can be reviewed to compare to real process and to confirm if it is right and complete.
2.4 Types of Flow Charts
There are four general flow chart types. These differ according to different perspective of people who modeled them:
- Document Flow Charts: They display controls over a document that flow through a system.
- Data Flow Charts: They display controls over a data which flows in a system.
- System Flow Charts: They display controls in a resource or physical level.
- Program Flow Chart: They display the controls in a program inside a system.
Whereas there are many classification of flow charts like that is showed in the up.
2.5 Conclusion
Flow charts provide a visual illustration and explanation of process to user. These charts are the first steps to understand each process. Also these charts inspire team work and involvement to the business by employee.
3. SCATTER DIAGRAM
3.1 Purpose of Scatter Diagram
Scatter diagram is mostly used when there is a need to identify the correlation of two variables that somehow affect each other, to observe the altering in one variable when the other one is changed.
3.2 Description
Using Scatter Diagram enables us to predict what kind of function is more suitable to present the relation of two variables. Two ways to demonstrate the relation between the variables are to determine the degree of relation numerically and graphically. Indeed, Scatter diagram shows the direction and quantity of the linear correlation of two variables. The direction and the quantity of the linear correlation of two variables are measured and defined by a phenomenon called correlation coefficient which is shown as “râ€. This r value is always between -1 and 1. In the case r=0 means, there is no relation between the variables. The higher “r†number closer to 1, the more positive correlation between the variables. On the contrary the lowest “r†number closer to -1, the more negative correlation.
In the figure below, the correlation between the waiting line between eruptions and the eruption duration of a geyser in USA. From the relation of two variables, what we can conclude from this diagram is, there are two types of eruptions. “Short wait-short duration eruptions†and “Long wait- long duration eruptionsâ€. The closeness between the points represents the level of correlation between variables, that are placed in X and Y axis.
3.3 Construction of Scatter Diagram
While making a Scatter Diagram, there are some steps in order, that should be followed:
- Choosing two items, that we want to examine the correlation between. Usually, it is better to use two variables that are potential for a cause and effect relationship. For instant, an effect and its cause can be the inputs for the scatter diagram
- Data gathering. As in the histogram, using as much as data will lead us to have more verified and accurate results.
- Placing the data points on to X and Y axis.
- Plotting the each set of paired data on to coordinate axis. There will be dots depends on how many data points we collected.
- Evaluation of the Chart and results.
3.4 Evaluation of the Scatter Diagram
The interpretation of the results we can detect from the diagram can vary depends upon the relationship presented indiagram. If there is a strong relationship between two variables, a change in one item will automatically affect the other one to change. But if there is no relation, a change in one will not affect the other one at all. So, the interpretation is divided into 3 categories;
- Positive relationship: The variable on the X axis is increases as the other one on Y axis increases, or vice versa. The slope of the best fit line is positive.
- Negative relationship: As the variable on the X axis increases while the other variable on Y axis decreases, or vice versa. The slope of the best fit line is negative.
- No relationship: There is no relation defined between the variables on X and Y axis. Their altering does not affect each other.
3.5 Conclusion
Scatter diagrams presents the user the correlations between a quality characteristics and a factor that might be affected with it. What make this quality tools so useful is that; it is easy to use, to interpret and to communicate to others.
4. PARETO CHARTS
4.1 Purpose of a Pareto Chart
The Pareto charts set priorities within the problems to decide which problems must be tackled first. Since no organization has enough resources to deal with all the problems, the prioritization is important. A pareto chart lists graphically the main points in a brief and shows the connected importance of the different points between data groups.
The purpose of Pareto chart is to stress the most important between set of factors. In quality control, it usually symbolizes the most usual origins of deficiencies, the defect types that have high frequency or the customer complaints’ most common reasons and etc. The Pareto charts are especially useful to improve the process in manufacturing.
4.2 Description of Pareto Chart
Italian economist Vilfredo Pareto developed the Pareto concept by depicting the frequency distribution of a population’s given characteristics. Pareto chart is a kind of chart which includes both a line graph and bars. The bars shows the values in going down order, and the line graph displays the cumulative sum up of each category, left to right.
Pareto charts set the data’s priorities from highest frequency to lowest. These charts determine the “ vital few “ classes which explains the largest connected frequencies and set apart the “ unimportant many “.
The Pareto chart can provide answers to the questions which will be helpful to find the largest issues that the business or team is facing, to get the highest rate of improvement where the team should focus their efforts.
4.3 Construction of Pareto Chart
To start to draw a Pareto chart, the range of data should be segmented into groups (segments, categories, bins, etc.). Then the categories or columns should be ranked order (begin with the highest frequency column on the left and continue to the right). Then the number of data points which exist within each group should be determined and the graphic should be prepared by paying attention to match the categories with frequencies. Above the data categories, a connected frequency line should be calculated and placed. This is the cumulative of each categories percentage.
The start point of construction of a Pareto chart is to choose a process which is not producing yields. If the process requires rework or scrap, then the reasons for this rework or scrapping these parts are identified and a list is made for the causes of problems. Now, we have enough amounts of data to make a chart. After making Pareto chart, it can see which problems are the most effective to cause trouble, there should be two or three which are outstanding. Then we can concentrate to these problems which are most troublesome. After using Pareto chart to improve the process, to check how the improvement worked, we can do another Pareto chart and the problems that are causing the largest harm and must be tackled, will be shown in this chart again.
In the Pareto chart example, frequency of occurrence showed in the left vertical axis. And the right axis represents the cumulative percentage of total number of occurrences. Since the numbers of reasons decreasing, the shape of the cumulative function is concave function.
4.4 Conclusion
There is no wrong problem or wrong process choice to use Pareto charts. To improve quality, the most important thing is doing something and starting from somewhere. To decide where your business has problems, if you start to use Pareto chart, you will find out several things about your business or processes and you will learn where to develop.
5. CAUSE AND EFFECT DIAGRAM
5.1 Purpose of Cause and Effect Diagram
Cause and effect Diagram plays an important role in order to come up with a good output from a project and to provide a continuous improvement process since it gives us the idea about the root cause or causes of the treats and problems throughout the project. One who chooses the cause and effect diagram as a graphical presentation will have the idea of what is the essential root cause that leads us for that particular quality problem.
5.2 Description
Cause and effect diagram is also one of Ishikawa’s seven quality tools developed in University of Tokyo in 1943. It has been using in order to determine, investigate and show the root causes of a problem or consequence. This diagram is also useful to display both all the related causes of a problem with the problem, in one diagram. This allows us to be able to see all the things in one page and will clear the situation. The Problem, consequence or the situation that we want to work on is written on the right side of the diagram, while all the possible related causes are written on the left side. As can be seen from the figure 5, the sub-causes are linked to the main causes, and they all together forms the fishbone. Since the shape is more or less look like a bone of fish, it is also called as “Fish Bone Diagramâ€.
It is clear that we can end up with the causes by starting from the problems by using statistical methods. But apart from that, what the cause and effect diagram gives us that it shows the direct and explicit relation between the consequences and their causes, visually. And the causes to display are mainly divided into 6 main categories; Man/People, Measurement, Machines/Equipment, Materials, Methods and Environment.
5.3 Construction of the Cause and Effect Diagram
The steps should be followed when making a cause and effect diagram demonstrated as the following:
- A project team for drawing the Cause and Effect Diagram is formed. It should be paid attention that the each member of the group has the pre-knowledge about the quality concern. One of the members is selected as the facilitator. S/he is the responsible to listen and note the ideas and thoughts presented by the other team members in an easy and understandable manner.
- The concern which is related the situation and needed to be improved must be identified as an effect, and draw a box around it and add an arrow towards to it.
- The next step must be the brain storming that must be held by the team members about what could be the entities causing this effect that is identified at previous step. Also the likelihood of relation between these causes, must be investigated.
- This step must be followed with the previous step. Because here, the sub-causes that are somehow related and affect the main causes must be identified and analyzed. Make sure that all the possible factors that contributing the main cause are defined. When preparing the diagram, environmental and business factors must be identified detail. And each team member’s opinion should be taken in order to define all the possible causes to the problem.
- The last step must be focusing the causes more in detail which an improvement plan can be developed for by using other quality tools and techniques. The causes will be focused must agreed by the team members.
5.4 Conclusion
Cause and Effect diagram are very effective and powerful among the quality tools in the manner that making a better understanding on our project. This diagram requires a team work, and pre-knowledge about the process project that we are working on. Since this diagram provides us an improvement for our project, it requires knowledge for sure. Because the more information that team members have, the more opportunity to improve them to come up with better outputs.
6. CHECK SHEETS
6.1 The Purpose of Check Sheets
Check sheets provide to collect data from a process in a systematic, organized and easy manner.
6.2 The Description of Check Sheets
Check sheet is a simple document which we use for data collection in real time and in the location where the data is created. The check sheet is typically a blank form which is designed to register the needed information in a quick, efficient and easy way.
Since the data collection is the beginning point of statistical analysis, it is very important and can sometimes become messy and unorganized exercise. Check sheet is a simple form that we can use for data collection in a structured manner and we can convert it into useful information easily. Check sheets present information in a graphical format effectively. A check sheet is a form or table which is used to register data as it is collected. Also check sheets help to organize collected data by category. They display that how many times each particular value happens, and the information that check sheets provide, is becoming more helpful as more data is collected.
The check sheets’ main application is to register data that shows how often different problems happen, and to register the frequency of incidents which are thought to be reasons of problems.
Check sheets are used to identify clearly what is being observed. The events that are being observed should be classified clearly. The data collection process should be taken easy and the data should be grouped in a way which makes data reliable and valuable. Similar problems must be in similar categories. Then a format which will give the most helpful information with the less effort should be created.
Check sheets are effective ways to display data and they are easy to use. They show the root reason of problems. Also check sheets are the first steps to construct other graphical tools. It provides an organized uniform data collection.
6.3 Construction of a Check Sheet
To create a check sheet first step should be defining the events, problems or processes to be recorded and to categorize these events. If there are events which are not easily categorized into any of the existing group, then a category of other should be added for these events.
Then for the data recording, suitable intervals and periods should be identified. This time interval should be representative. And the check sheet should be designed to be used during data recording and it should be easy to understand. All columns should be properly classified. The data collection should be performed during the agreed time interval, and everyone should understand the tasks and events that are recorded. The data should be analyzed to identify events with unusually high or low frequencies. Then the information should be plotted on a check sheet.
There are four main types of check sheets:
6.3.1 Defective Item Check Sheet
To identify what types of defects or problems occur during the process, this type of check sheets are used. In these check sheets there is usually a list of problems or defects that can occur during the process. When a defect or problem occurs, a mark is placed in the column of this problem. The data that is used is countable in this type of check sheets. The table below shows an example for a defective item check sheet used in wave solders manufacture process.
Defect Type |
Insufficient Solder |
Cold Solder |
Solder Bridge |
Blow Holes |
Excessive Solder |
Frequency |
xxxxxxx |
xx |
xxx |
xxxxxxxxxxxxxx |
xx |
Total |
7 |
2 |
3 |
14 |
2 |
Table 1. Wave Solder Defect Count
6.3.2 Defective Location Check Sheet
This type of check sheets helps to find the location of defect or problem on the product. These are used if the external appearance of products is important. This type of check sheets generally consist a picture of product. To indicate the place of defects that are occurring on the surface of the product, marks can be made on the picture.
6.3.3 Defective Cause Check Sheet
This type of check sheets are used to find the causes of defects or problems. During data collection, more then one variable is monitored for this type. For example, the data about type of machine, date, time and operator can be monitored in the same check sheet. Table below is an example of this type of check sheets. As it is seen from the table, most of the error is occurring in the afternoon shift and in the machine 2. This means that machine 2 has problems when it is used in the afternoon shift.
Machine 1 |
Machine 2 |
||
Operator A |
Morning |
X |
X |
Afternoon |
XX |
XXXXXX |
|
Operator B |
Morning |
X |
XX |
Afternoon |
XX |
XXXXXXXXX |
Table 2: Defect cause check sheet
X= Number of times that there is an error occurs
6.3.4 Checkup Confirmation Check Sheet
To being sure that proper procedures are being applied, this type of check sheets is being used. This type of check sheets generally has a list of tasks which are required to be accomplished before the action will be taken. Final inspection, operation checks, service performance, machine maintenance check sheets are the examples of checkup confirmation check sheets.
6.4 Conclusion
Check sheets are helpful methods to collect data. They are easy to use and understand and also they let user to collect data in an easy, organized and systematic manner. There are many types of check sheets are being used. The most common types are defective item, defective location, defective cause and checkup confirmation check sheets.
7. CONTROL CHARTS
7.1 Purpose of Control Charts
It is a tool used to ensure that whether the business or production process is under control continuously and to help the improvement of the process performance by the studying variation and its source. Using control charts will help us to make the adjustments of the quality of output of the process where it is needed.
7.2 Description
Control charts are formed in order to examine if the process is statistically in control and the variation of the process within time. Control charts give us notice in advance of possible problems that can be happened in near future. By the control charts one can interpret about the variation that are obtained from the data of a process and keep the process in control. And the method used is called Statistical Control Process. The aim of the control charts is to keep the variations that might be occur during the project in the quality manner within acceptable the upper and lower limits. Control charts only give notice to us about the existence of defect; it does not give any solution to overcome it. Here are some benefits to use Control charts;
- To expose the essential changes of the quality properties.
- To measure quality change performance.
- To determine the average level of the quality properties.
On control charts 3 levels must be defined. These are Upper control limit (UCL), Center line (CL) and lower control limits (LCL).These limits or lines are calculated from samples that are taken from the particular process. And the points in the chart refer to the samples and usually minimum 25 points are required to come up with an accurate control chart.
According to the data type we have, selecting the best suitable control charts, will lead us to reach the result faster and efficiently. Types of control charts can be defined mainly defined as the average and range control charts. The average control charts show the closeness of the process to the nominal design value, while range control charts indicate the quantity of variability and spread around the nominal value.
7.3 Construction of Control Charts
Construction of a control chart involves three main steps:
7.3.1 Mathematical Model
Step 1: Data Collection
First we need to decide which quality characteristic of the process or product will be examined. Then m samples of n units are chosen for controls. For each unit, the determined quality characteristic is measured and recorded in a spreadsheet.
Step 2: Plot data In each case, the X axis of a control chart shows sample numbers. Data plotted depends on the chart type for the Y axis:
Step 3 : Calculate the central line and control limits
The table below shows the information about central lines and control limits for both types of control charts :
The coefficients used in formulas depend on the sample number n and they are shown in quality books.
PART TWO: THE SEVEN MANAGEMENT TOOLS
The seven management and planning tools are used in isolation or in an integrated fashion, are designed to improve planning and implementation, it may require more time during the planning stage, and it is intended to save time later as a result of better planning.
The Seven Management tools are the following;
- The Affinity Diagram
- The Inter-Relationship Digraph
- The Tree Diagram
- The Activity Network Diagram
- Prioritization Matrices
- The Matrix Diagram
- The Process Decision Program Chart
1. AFFINITY DIAGRAM
The origin of the affinity diagram can be traced to a data analysis technique called the KJ Method, developed by Kawakita Jiro. The affinity diagram is largely a creative brainstorming process in which consensus is reached by visual (written) rather than verbal means. The affinity diagram can also be used as a management and planning tool that can help with the systematic analysis of large amounts of data. It is best used for translating large amounts of complex, apparently unrelated information, into natural and meaningful groupings of data.
Grouping related items helps to identify underlying relationships that tie ideas together. Clues about potential strategies for overall problem solving are revealed that can help discover new a structural pattern in performance improvement relationships. This tool organizes language data. Once brainstormed ideas are written on cards, they are grouped together with similar ideas (affinities) a header card is created which captures the meaning of each group of ideas. This is a creative, “right brainâ€, activity. In order to dilute the power of institutionalized ways of thinking about a perceived problem, the affinity diagramming process encourages a group to step outside their logical perceptions and apply their professional intuition. This process is also an effective method to use to generate a large number of ideas in a brief period of time.
1.1 Advantages of Affinity Diagram
- A team can generate a large number of ideas in a relatively short period of time.
- Encourages participation because every person’s ideas find their way into the process.
- Encourages ‘new’ thinking when only ‘old’ solutions are emerging from a group.
- Facilitates the exploration of new and logical thought patterns by encouraging people to react from a creative response level rather than the intellectual and logical levels.
- An effective way to deal with large and complex issues which may be ‘paralyzing’ the brainstorming of a team.
- Consensus and support are reached on a solution because all participants have ‘ownership’ in the process.
1.2 When to use an Affinity Diagram
- defining the nature of a problem or opportunity or bringing out hidden problems or opportunities
- helping to organize and order fuzzy ideas
- showing the proper direction to take in solving problems or meeting opportunities
- It is used when the chaos exists;
- Broad issues / themes must be identified.
1.3 Constructing an Affinity Diagram
- Assemble the right team: Four to six people with varied perspectives who are creative and open-minded.
- Phrase issue to be considered: A clearly stated, yet broad, neutral statement which is well understood.
- Generate & record ideas: Follow brainstorming rules & records each idea on cards and flip chart with no one word cards.
- Randomly lay out completed cards: On a table, wall, or flip chart;
- Sort cards into related groupings: Quickly & in silence based on gut reactions. If you disagree – move cards, do not discuss.
- Create the header cards: These should be concise, but complete with no one word headers – they should make sense as stand-alones. This should capture the essential link in all ideas beneath it as well as what the cards are saying about that link. Place these at the top of each grouping and turn sub themes into sub headers.
- Draw the finished affinity diagram: Draw lines connecting headers and sub headers with all the cards beneath them. Bring together all the related groupings and then begin review of the diagram by team members and important “non- team membersâ€.
1.4 Affinity Diagram: Construction/Interpretation Tips
- Keep the team small;
- Make sure that ideas are clarified, not criticized during brainstorming;
- Avoid one word cards – they are often ambiguous & cliché;
- Write clearly – large letters – use felt tip points if possible;
- Use flip chart to keep ideas visible as they are recorded on cards;
- When possible, the statement should have both a noun & verb;
- Don’t agonize over sorting;
- Enforce the silence rule during sorting – discussion is allowed when header cards are created;
- Keep the process moving — prevent stagnation.
- The “final†product should be reviewed by others and modified as needed.
2. INTERRELATIONSHIP DIGRAPH
Interrelationship Digraph follows the Affinity and identifies the primary issues based on root causes. “It separates the vital few from the trivial many.†An interrelationship digraph is a visual display that maps out the cause and effect links among complex, multivariable problems or desired outcomes.
2.1 When to use an Interrelationship Digraph
The tool is exceptionally adaptable to both specific operations issues as well as to general organizational questions. It is equally applicable to core work processes (linking clients to resources) as to support processes (developing the capacity to view work through a prevention lens).An issue is sufficiently complex that the interrelationship between and among ideas is difficult to determine, The correct sequencing of management actions is critical, There is a feeling that the problem under discussion is only a symptom, also
- Root causes must be identified
- A large number of inter-related issues need to be better defined
- Scarce resources require focused effort
- When you need to graphically map out the cause and effect links among all items generated.
- Identify the issues/causes that are most fundamental among all the related items.
2.2 Constructing an Interrelationship Digraph
- Identify the areas for which you wish to determine the interrelationships.
- Clearly display the areas for the entire group to see.
- Consider the relationship between each of the areas two at a time. For example, if you have 4 areas, consider two at a time, and ask the question, “Which of the two most strongly influences the other?†Draw an arrow between the two that indicates the direction of influence. Recognize that the influence may go both directions, but seek to determine which direction the influence is strongest. Continue to ask this question until all of the pairs have been considered.
- For each area, count the number of arrows going out and the number of arrows coming it. The area with the most arrows going OUTWARD is the area with the strongest overall influence. It is, therefore, an important area to consider in the planning place – it’s influential. Likewise, look for the area with the most arrows coming INWARD. This area is the one that is most often on the receiving end of other factors. It also requires special attention to ensure that influences (arrows) coming to the area are coordinated so that the area isn’t overwhelmed by competing influences. For example, if front line workers are confronted by conflicting policies, programs and planning efforts, it challenges their ability to translate them into effective daily practices.
3. TREE DIAGRAM
It is a way to systematically map out in increasing detail the full range of paths and tasks that need to be accomplished to achieve a primary goal and each related sub goal. It is known as systematic diagram, tree analysis, analytical tree, or hierarchy diagram. It is used to divide different categories into specific and finer levels of detail. The tree diagram development helps us to move generalities to specifics thinking. The tree diagram starts with one item that divide into two or more parts, also each of which branch into two or more parts, and so on. It looks like a tree, with trunk and multiple branches
3.1 When to use a Tree Diagram
- Broad objectives must be broken down into specific implementation detail
- All of the implementation options must be explored
- Assignable tasks must be created
- It is used when evaluating implementation issues.
- It is a communication tool, which is a very brief explanation to others.
- It is used when figure out the major actions require to carry out a solution.
- It is used when analyzing processes in detail.
- It is used to identify for the root cause of a problem statement.
3.2 Tree Diagram Procedure
- The first step to define the goal statement and it must be written on the top.
- The goal is according to the SMART criteria, like S for Specific, M for Measurable, A for Achievable, R for Realistic and T for timely.
- Also check that all necessary items are according to the level necessary for of the above level, also check that all items at this level are present, also check that it is sufficient for the above level.
- The tree will be growing by putting new ideas and each idea must be a goal, problem statement or objective, and for each new idea we have to use the SMART criteria, so with the usage of SMART criteria we can develop the new tier of statements which can show the relationship with the above tier of goal or ideas with the help of arrows.
- Continue this practice again and again and turn the ideas into subject statement, we must continue this process until we can reach to the fundament elements, and to identify that what are the specific actions that can be carried out.
- Perform the Necessary check again to the whole diagram, and verify that all the items are sufficient for the objective, and verify that all the items were present and confirm that it is sufficient for the objective to be achieved.
Customer Satisfaction Improvement Plan
4. ACTIVITY NETWORK DIAGRAM
- Developed by the U.S. Department of Defense
- Also known as the Program Evaluation Review Technique (PERT) or Critical Path Diagram
- Tool used to control the length of projects
- Takes into account many aspects of projects: task times, slack times, critical tasks, etc.
- Designed for research and development-type projects
- Determines a probability distribution for a project
- To plan the most appropriate schedule for the completion of any complex task and all of its related subtasks.
- It determines total implementation time, simultaneous tasks and key subtasks to be monitored.
- The task is complex
- The subtasks are familiar with known durations
- The project is a critical organization target
- Simultaneous implementation paths must be coordinated
- There is little margin for error in the completion time
4.1 When to use an Activity Network Diagram
- Brainstorm ideas of where activity network diagrams could be utilized in your business practices
- Finding minimum completion times
- Determining maximum completion times
- Value of time for each step in the project
- Assigning specified times for parts of the project
- Creates a realistic schedule for the company
4.2 Procedure for development
- All preceding activities must be completed before the project can begin
- The arrows shows the logical precedence of the project
- Identify all necessary activities and identify the relationships among them
- Draw the diagram
- Estimate each activity time, or node, in the diagram
- Identify the critical path
- Study the diagram for milestones and the target dates in the overall project
5. MATRIX DIAGRAM
The matrix diagram shows the relationship between different items or relationship between 2, 3, or 4 groups. The information about the relationship is like its strength or the role played by different individuals or measurements. “Six different shaped matrices are possible: L, T, and Y.X.C.and Roof-shaped depending on how many groups must be comparedâ€
L-Shaped |
Two groups |
A B or A B |
T-Shaped |
Three groups |
B A C but not C B |
Y-Shaped |
Three groups |
A B C A |
C-Shaped |
Three groups |
All three simultaneously (3D) |
X-Shaped |
Three groups |
A B C D A but not A C or B D |
Roof-shaped |
Open group |
A A when also A B in L or T |
Table 4: differently shaped matrices
5.1 L-Shaped Matrix Diagram
The customer’s requirements are summarised in the L-shaped matrix. This is the most basic, important and common format of matrix. The name of customers are placed horizontally while the numerical specification vertically and check marks are showing the packaging choice. The L- Shaped matrix is formed an upside-down L.
Customer X |
Customer Y |
Customer Z |
Customer W |
|
Purity % |
> 99.3 |
> 99.3 |
> 99.5 |
> 99.0 |
Trace metals (ppm) |
< 5 |
— |
< 11 |
< 25 |
Water (ppm) |
< 10 |
< 5 |
< 11 |
— |
Viscosity (cp) |
22-35 |
22-30 |
10-60 |
15-35 |
Color |
< 11 |
< 11 |
< 15 |
< 11 |
Drum |
||||
Truck |
||||
Railcar |
Table 5: Customer Requirements
5.2 T-Shaped Matrix Diagram
â€The T-Shaped matrix is used to show the relationship between two different factors and how to relate to a third factorâ€[19]This T-shaped matrix relates different product models, (group A) Showing their manufacturing locations (group B) and to the customers (group C). We can examine the matrix in different ways and collect different information. If we see to model A we see that in large volume of the product is produced in Texas and at Alabama in little volume. The major customer for group A is Time In while small amount is bought by Arlo Co. Now if we see customers row we see that the purchaser for all four model is Arlo,While only one model is bought by Zig.The minor customer is Lyle and the Time is the large purchaser of A and D.
5.3 Y-Shaped Matrix
The Y-shaped Matrix shows connection between internal process metrics, the involved department and the customer’s needs. The strength of relationship is shown by symbols. Primary relationships such as responsibility of production capacity by manufacturing department. Secondary Relationship as the link between the product availability and register level and the Minor relationship is the responsibility of distribution department for order lead time, while no relationship is on time delivery and purchasing department. In the matrix the primary responsibility for the customer’s requirements is assigned to distribution department’s which is the most strongly related metrics to on time delivery are the inventory levels and order lead-time. Distribution has the weak relation ship with order lead time and non-with inventory levels.
5.4 C-Shaped Matrix Diagram
As the name of the matrix is C matrix which means cube, this is three dimensional. We can compare three groups simultaneously using computer software or 3 dimensional models. The following figure shows the relationship of customers, locations of manufacturing and relating product.
5.5 X-Shaped Matrix Diagram
The T-Shaped matrix is Extended into X-Shaped matrix when the relationship of goods transportation (freight) with manufacturing sites they serve and the users(customers)every axis of the matrix is linked to the two adjacent ones, but not to that one cross. So the sites of plants and the customers are related to the product model but they are not related to freight line.
We see in the following X-matrix that the red line and Zip inc seems to be small carriers on volume based, but are the only one to serve Lyle Co. The customers for model C are Arlo and Lyle Co. At 3 locations Model D is made while all others are made of two.
5.6 Roofed-Shaped Matrix Diagram
It is used with L or T shaped matrix showing one group of items. With a house of quality it is mostly used. We can see in the figure that the customer requirement are related to each other.Color and trace metals are strongly linked, while the viscosity is unrelated to any other requirements in the figure below.
6. PROCESS DECISION PROGRAM CHART (PDPC)
The PDPC systematically find that what might go on wrong side in a plan under development. To prevent or offset the problem arises countermeasures are developed. The PDPC helps both to revise the plan under development to avoid the forthcoming problems or also the best response when the problem occurs.
6.1 When to use PDPC
- We can use the PDPC before implementing a plan especially in large and complex plan.
- In those plan which must be completed on time schedule.
- In those plan where the failure of price is high.
6.2 Procedure of PDPC
- For the proposed plan a tree diagram is obtained or developed. The diagram should be of high level, which shows the objective, the 2nd level objective of main activities, and 3rd level of objective of broadly explained tasks to accomplish the main activities.
- Brain storms what could be wrong for every task on the third level.
- The potential problems are review and any improbable are eliminate. The problem as fourth level linked to the given task.
- Brainstorm possible countermeasures, for every potential problem. These are might be changes to the plan that would put off the problems, which would remedy it, occurred. Shows the countermeasures as 5th level, jagged lines or outlined in clouds.
- Decide how practical every countermeasures is. The criteria like cost, the ease of implementation, the time required and the effectiveness. The impractical countermeasures are marked with X and the practical countermeasures with an O.
Example of PDPC
“Here is an example of medical group who is planning to improve the patients care with illnesses like asthma and diabetes through a new chronic illness management program(CIMP)â€[1].The four main elements are defined by them and for every elements and key components the information is PDPC chart below.In the chart the dotted line present the omitted part of the chart. The planning team shows some of the countermeasures and potential problems on the chart below.
With the patient’s one of the possible problem “goal setting is back sliding. The idea of friend or sponsor with each patient is the idea of the team and that will be add to programme design. The other areas in the chart help them to rollout, like the visit of staff arrangement to their clinic with CIMP programme. But still one of the areas allows the group to plane in advance for arising problems. Such as the training of the CIMP nurses that how to counsel the patients with inappropriate goals.
7. PRIORITIZATION MATRIX
It is a useful technique and we can use with our team members or any other users for achieving the consensus about an issue. The matrix helps us to rank problems or issues by a particular principle, which is important to our organization. Than we can, more clearly see the problems with priority to solve first.
7.1 Who, Why and When to use
Member of a team or participants in a group who participate in the process. To determine what our users or our team members consider being the most serious problem with our program. When we need to prioritize the problems, or to achieve consensus about issue.
7.2 Using a Prioritization Matrix
- Brainstorm: first we have to conduct a brainstorm session on the problem, which group members or team members are facing.
- After brainstorming the prioritization Matrix chart is fill out with the group.
- In the first column, the problem are written which are mentioned in the brain storm meeting.
- In the second to fourth column criteria are defined. we have the following example of some criteria
Frequency: In this column we write that how frequent the problem is? Does this problem occur often or rarely on some occasions.
Importance: In the column we write that how important is the problem from the users point of view. What are the problems to be resolved?
Feasibility: What is the practical approach to resolve the problem? Will it be hard or easy to resolve it?
We can also choose other criteria, which better fit to the situation. For example we can add quantities like cost, amount of time and other numerical indicators.
Rank: Each participant according to the table above votes four times for each criterion. And every participant votes 12 times in total of all votes: The total votes clearly help you to observe that how to prioritize the problems
CONCLUSION
In this seminar report, we discuss about Seven Quality tools and Seven Management Tools, In our seminar report first part, we explain briefly the seven quality tools, At this stage Ishikawa’s seven quality tools are quite helpful to determine, identify and evaluate the problems, their causes and suggestions for a continuous improvement process. These tools can be listed as; Histogram, Flow Chart, Scatter Diagram, Pareto Chart, Cause and Effect Diagram, Check Sheet and Control Chart. In the second part of our seminar report we briefly describe about the seven management tools, The seven management and planning tools are used in isolation or in an integrated fashion, are designed to improve planning and implementation, it may require more time during the planning stage, and it is intended to save time later as a result of better planning. These tools can be listed as; The Affinity Diagram,Inter-Relationship Digraph,Tree Diagram, Activity Network Diagram,Prioritization Matrices, Matrix Diagram and Process Decision Program Chart.
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