In Six Sigma, a well thought out and proper Process Design is very important for the process to be efficiently implemented for a longer term. A process can be designed for an existing process which has no proper design and documentation or of course a new process that is being created from ground up. For this exercise of process design, its very important to first identify the various tasks in that process then identify the roles (people or groups or departments) and finally their responsibilities for a given task. Not all roles have a responsibility towards a task and a given task may not be associated to all roles. Typically a task is associated with at least one role or in some cases multiple roles. This ‘Association’ of the role with a task can be divided into the following four association types:

• Responsible
• Accountable
• Consulted
• Informed

The above four types of association of a role to a task represented in a simple task vs Role diagram or Matrix is called RACI (pronounced ‘racey’) matrix. So basically the RACI matrix is a responsibility assignment matrix (RAM), designed to assign tasks, activities, responsibilities, accountability, decision making, supporting to team members of a process/project  and clarify expectations on the level of their participation.

There is another association type that is some times used in addition to the above four types:

• Supports

When you use all the five types in the matrix, its called RASCI (pronounced ‘race ski’) Matrix. Lets go thru each association type in detail below:

Responsible

The role or person or entity that is assigned the role type ‘Responsible’ is the one who performs the work. In other words he/she is the ‘doer’ of the task or activity. The person who is ‘Responsible’ need not be accountable for that task, even though in some cases the same person can be ‘Responsible’ and ‘Accountable’. The degree of ‘Responsibility’ can vary and multiple roles can share the responsibility of a single task. Also the responsibility can be delegated by the role to another role. Using the RACI matrix we can see if a role has too many or too few responsibilities and try to adjust the work load.

Accountable

‘Accountable’ is the person or role who has the final authority and accountability to a given task. For any given task, there is only one role/person accountable. This accountability can’t be delegated to other roles or individuals or entities.

Consulted

‘Consulted’ are the people/roles who are consulted and taken advice from before and during performing the task. When there are many people who are assigned as ‘Consulted’ roles, the time take to accomplish the task increases. On the other hand too few or no ‘Consulted’ roles assigned to a task means that task has the risk of being under performed .

Informed

Informed are the people/roles who are informed after the task is completed. You need to assigned the ‘Informed’ roles properly as otherwise it may lead to mis communication and delays. You need to make sure the right people/roles are informed after a task is performed successfully.  If too many roles are informed after a task, we need to see if its necessary to do so and minimize on that.

Supported

‘Supported’ are the roles/groups/departments that provide the resources and hence support that task. This is an optional role type and if the matrix uses this category along with the other four RACI categories, then its called ‘RASCI’ matrix.

RACI Diagram

Why do we need RACI?

• RACI is a good communication tool. Without RACI, six sigma processes will result in poor communication and improper process definition and poor hand-offs
• RACI makes sure each and every task is owned by a role
• People tend to think think they are the ones who are responsible and/or accountable where as they might actually be in ‘Consulted’ or ‘Supported’ roles. Assigning wrong roles results in duplication of effort and misunderstanding and fighting.
• RACI allows the right people to be assigned to the role of consulted.

RACI Benefits and Advantages

• Activities and tasks in a six sigma process are well defined thru brainstorming.
• By clarifying roles and responsibilities at the very initial stage of the process design, RACI helps setting up the proper expectations among team members and hence reduces future misunderstandings.
• Eliminates duplication of effort
• RACI helps improved communication by setting up the proper expectations among team members at the very initial process design stage.
• Identifies the owner of a task clearly and assigns accountability to that role.
• By ensuring that the correct people are involved, RACI helps in avoiding wrong decisions.
• RACI clarifies hand-offs and task/role/responsibility boundaries.
• Improves understanding of cross-functional view for employees  across divisions or departments, and helps employees across various groups respect and appreciate the roles and duties of people from other groups.

 Step by Step procedure to create RACI Charts

1. Determine the functions, decisions, tasks and activities that will make up the process or project.
2. Identify who will be the project’s participants.
3. 1,2 will make up the rows and columns of the RACI chart.
4. Identifying how each participant is involved with each function, decision,task, activity.
5. Fill out the grid with the letters R(responsible),  A (accountable), C (consulted), or I (informed)

RACI Example

Lets take the simple two task example of designing the process for content management.

Task 1: Create Content

• The Creative Team is the party that is responsible for doing or developing a content piece. So they are assigned a role of R.
• The Marketing Team/Department is the Accountable party and assigned the role A and they own this process.
• The IT team needs to be Informed when this task is completed, so IT Team is assigned the role of I.
• The Legal Team responsible for Consulting and approving this content. Also they need to be notified when this task is done. They will be assigned C,I and even R

Task 2: Upload the content

• The IT team is Responsible for the task of Uploading the content and Publishing it. Their role is assigned with R
• The Marketing team is accountable and needs to be informed when this task is completed. So they are assigned A,I.

Discoveries/findings from RACI Chart

• Each task/function/activity (row) should have ONE and only ONE Accountable (A).
• Each task/function/activity (row) should have at least one Responsible. In some cases, a task can have more than one role responsible with shared responsibility.
• If a task has more than one R then the task should be brainstormed further and see if it can be split into two tasks.
• The number of Consults should be minimized.
• Too many I’s is also not a good sign. Minimize the I’s so that only those who need to be Informed are informed.
• If a column has no empty spaces, that means that Role/Person is involved with all tasks.  See if you can reduce C’s and I’s for this Role.
• If a column has many R’s – The role may have too much work to do. Try to break the task into small sections and delegate to other roles.
• If a column has no A’s or R’s, may be this role can be eliminated from this process.
• If a column has many A’s means this role be a bottleneck. Try to see if these tasks be shared.

1. Collect customer’s requirements/desires as specified by the customers in their own words
2. Prioritize these desires
3. Translate them into engineering/process requirements
4. Establish targets to meet the requirements.

QFD is also termed as:

• Voice of the Customer
• House of Quality
• Customer-Driven Engineering
• Matrix Product Planning

QFD is a customer driven product or service planning process. It is a methodology for translating customer requirements into company requirements at each stage from Concept Definition (R&D) to Process Engineering and Production and into the marketplace. The QFD matrix is a tool to translate CCRs (Critical To Customers) into CTQs (Critical to Quality).

QFD collects the voice of the customer (VOC) in their own lingo and incorporates this VOC into the companies cross-functional team’s project management of the integrated development process. The QFD process establishes customer objectives and measures and records them on a series of matrices

This QFD matrix

QFD matrix translates the CCRs into CTQs. The final score helps prioritize the CTQs and helps you decide which CTQs to tackle first.

The QFD Methodology

• Identify both internal and external customers.
• Create a list of customer requirements/desires (Whats) by
  • Asking the customer, questions such as “What are the important features of  The Product”
  • Capturing the customer’s own words or “Voice of the Customer” or VOC
  • Categorizing the Whats into groups/buckets if needed.
• Prioritize the above collected Whats on a scale of 1-5, with 5 being the most important. This ranking is based on the VOC (Voice of Customer) data. The CCRs (Whats) are listed vertically in the first column and all related CTQs (Hows) are listed horizontally across the top . In the second column, assign 1 to 5 based on the importance of the CCRs, where 5 is the most critical to the customer.
• Score each CTQ (Hows) on how strongly it correlates to each CCR. Remember we are looking at the absolution value of the correlation. It could be either positively correlated or negatively correlated. Use 5 for a strong correlation and 1 is a weak one. Leave it blank if there is no correlation. Some CCRs will have few CTQs that relate and rest unrelated.
• Compile list of CTQs (Hows) necessary to achieve the CCRs (Whats.)
• Translate the CCRs from VOC (Whats) into CTQs (Hows)
  • Arrows show direction for improvement (up for increasing, down for decreasing, etc.)
• For each What, find out the correlation with each How. If the correlation is strong use 5. If its week use 1. If its in between, use a number 2,3,4 based on how strong the correlation is.
• Next multiply the importance rating for the CCR by the correlation score for each CTQ.
• Add up the scores vertically for each CTQ and place that value in the bottom score row.
• Once the score is computed for all CTQs, the ones with the highest scores are the highest priority Six Sigma project objectives to work on.

SIPOC is a Six Sigma tool used in the phase 1 or the “Define Phase” of the DMAIC process, to gather information about any process. SIPOC stands for: Suppliers, Inputs, Process, Output and Customers. A SIPOC tool is usually an Excel spreadsheet which lists all the five elements into five columns as shown below. In this SIPOC diagram, we are describing a process of upgrading the memory of a laptop.

What does SIPOC Include?

SIPOC shows a clear understanding of the process by including:

• All the Suppliers who provide the inputs and services to the process.
  • Suppliers are individuals or divisions that supply inputs to the process.
  • Suppliers can be can be internal such as department, division, or individuals
  • Suppliers can be external such as vendors, government.
  • It is also possible that a supplier is also a customer.
  • In our example of upgrading the memory of a Laptop process, the suppliers are:
    • The Mechanic who provides his services
    • The vendors who supply the Memory, tools,
    • The utility that supplies electricity.
• All the Inputs needed, including all raw materials, services, information.
  • In our example of upgrading the memory of a Laptop process, the inputs are the Laptop, Memory, Tools, Electricity.
• The Process as depicted as a sequence of actions represented by a Flowchart diagram.
• Outputs of the process are the products, services, information that comes out of this process and is used by the Customers.
  • In our example process, the upgraded Laptop and the old memory modules removed from the laptop.
• The customers are the users who will use the outputs produced by the process.
  • In our example process, the customer is the Owner of the laptop.

How to create a SIPOC

• SIPOC creation is a team activity.
• Brainstorming must be done to discover details about a process, especially if its a new process.
• All the stakeholders of the process must be part of this brainstorming.
• Brainstorming must be done for each of the five elements: suppliers, inputs, process, outputs and customers of SIPOC.
• If the process is new, it is a good idea to start SIPOC from customer and move backwards to supplier.
• For an existing process that needs to be documented, SIPOC diagram is best created by first defining the process flowchart, and then identify inputs, outputs, customers, and suppliers.

Advantages of SIPOC

• Helps us understand the purpose and the scope of a process
• If lists all the suppliers clearly so we can see who is supplying to the process.
• It gives us insight in to all the inputs of a process
• It gives us insight in to all the outputs of a process
• Graphically shows the process as a flowchart/sequence of actions so the new team members can easily understand the process.
• All the customers are clearly identified, who will use the process outputs.

What are the differences between QFD and SIPOC?

Even though both QFD and SIPOC are used in the define stage of DMAIC, they are different.

• SIPOC helps define a process where as QFD is used to take the customer’s voice and translate into engineering/process requirements.
• SIPOC identifies suppliers, Inputs, process, Outputs and Customers where as QFD is used after SIPOC to gather customers voice and translate into CTQs (critical to quality)

Scatter plots show large amounts of data in a chart form. When the points on the scatter plot come closer making it a straight line, the correlation between the variables is higher and the relationship between the variables is stronger.

Correlation Coefficient (R) and Coefficient of determination (R Squared)

Correlation Coefficient is measured as:

R = [N * Sum(XY) - Sum(X)*Sum(Y)] / SQRT [N * Sum (X^2) - (Sum(X))^2] * SQRT [N * Sum (Y^2) - (Sum(Y))^2]

R is always between -1 and +1

Coefficient of determination is the square of R or R squared. This is always a positive number between 0 and +1

If the straight line goes up from left to right with higher values of X  corresponding to higher values of Y then the correlation is said to be  positive. A perfect positive correlation is of value +1. A good example of perfect positive correlation of +1 is the case where you use X grams of flour to make Y grams of Cake. As X increases Y increases proportionally and the correlation is equal to +1.

If the straight line goes down from left to right with higher values of X  corresponding to lower values of Y then the correlation is said to be negative. A perfect negative correlation is of value -1. A good example of perfect negative correlation of -1 is the case where  you have X amount of money in the bank and Y amount of additional money needed to become a millionaire. As X increases Y decreases   proportionally and the correlation is equal to -1.

If there is no relationship between the variables, then the plot does not look like a straight line, rather it looks “scattered” all over the XY plane. If there is no correlation between the variables then the correlation value is 0.

The correlation value thus ranges from -1 to +1. As the correlation number gets closer to +1 or -1 such as 0.8991 0r -0.9023 then the relationship is said to be stronger. If the correlation number is closer to 0 such as -0.1023 or + 0.122 then the relationship is considered to be week.

In the Measure stage of DMAIC, the data is collected. Then this data is reviewed by the team. Typically the data collected is is of two types:

1. Discrete data (true/false, fail/pass, success/failure )
2. Continuous data (example: frequency, color, time). Histograms are best suited for representing this data.

Histograms can provide a visual display of such data by dividing this large data into a finite number of groups or buckets. Once the buckets are defined, you need to match and find out for every number what bucket it belongs to. Once a number is assigned to a bucket, you need to increment the frequency value of that bucket. Once all numbers are counted, you take the buckets and their frequencies and represent them in a bar chart with buckets on X axis and the the frequencies on the Y axis.

• Histograms are used to understand how the output of a process effects customer expectations
• They will help you find out if the process is capable of meeting customer requirements
• Histograms are graphs of a distribution (frequency of occurrence) of data.
• Histograms show centering, dispersion (spread), and shape (relative frequency) of the data.

Lets take the example of a part (a screw) which is manufactured at a plant. The ideal diameter of the screw is 52.3 mm. Lets measure the diameter of a random sample of 16 screws. The diameters are measured as below:

52.1 52.2 52 52.3 52.2 52.5 52.3 52.3 52.2 52.1 52.6 52.4 52.3 52.4 52.5 52.4

Lets group them into the following buckets:

52
52.1
52.2
52.3
52.4
52.5
52.6

Now lets count how many screws belong to each bucket and compute the frequency

The above data can be represented as a bar chart as shown below:

In Microsoft Excel, you can create a histogram very easily using the “Analysis Toolpack” Add-In. (Go to File/Options/Add-Ins and make sure the Analysis ToolPak AddIn is installed). All you need to do is input your data (in our case all the diameters) into a sheet. You can use one single column or multiple columns. Also decide what your buckets are. Put them in a separate column. Now go to data menu and choose Data Analysis/Histogram. For the Input range, choose the appropriate Excel range containing the diameter data. For the Bin Range choose the column that contains your buckets. For the output, you can choose a range or a new sheet option. Click OK and Excel will automatically create the histogram table and Chart for you. No need to count and find out manually the frequency. Its done for you by the Analysis Pack histogram tool.

When the quality level of a process is not very high, we can use the basic six sigma tools. Typically the sigma level for such processes is 2σ or 3σ. Once the quality level gets better pass beyond 3σ, we will need to use more sophisticated tools such as DOE (Design of Experiments), SPC (Statistical Process Control) and DSS (Design for Six Sigma).

How to identify improvement opportunities ?

1. Identify the top 10 problems with high variation, top hidden factory problems, backlogs, or high down time issues.
2. For each of the above problems, identify all the underlying processes.
3. Pick the processes that are:
   • Very well defined
   • Have easily identifiable starting and ending points
   • Have clearly defined objectives

Do Not Pick

1. Processes that are being fixed by another team
2. Problems for which the solution is identified but causes of the problem are not known

Once you go through the above list, you will have now identified a bunch of processes that meet the above criterion. Now you need use “Selection Grid” or “Selection Matrix” method to prioritize from this list and pick the process with the highest “Selection grid/Matrix Score”.

Selection Grid/Matrix

We need to identify and define all possible criterion to which each of these projects can be measured. Good examples of criterion are:

• Doability by the existing team (resource criterion)
• Financial Viability (Financial criterion)
• Importance to other divisions (Cross division/company criterion)
• How important is it to the customer (Customer Criterion)

Once you define these criterion, assign a weight-age on a scale of 1 to 3 to each of the above criterion.

Create an excel worksheet with a table containing criterion along the horizontal axis (columns) and the projects along the vertical axis (rows). Insert one row above the criterion labels and in that put the weight of the criterion (which is a constant across all projects). Now for each of the projects, define how well it meets a given criterion on a scale of 1-5. Put that number in the cell corresponding to the Project row and criterion column. Once this grid is filled with the scores for all projects for all criterion, we need to compute the overall score of the project which is the sum of products of criterion weightage and the project score for meeting that criterion.

For example, for project 1, the score is: 1X3 + 3X2 + 3X1 + 3X3 + 2X2 + 5X1 = 30

Once the total score is computed for all projects, you can order them in descending sort order and the top project with the highest score is the first choice to pick.

Click on the buttons to show the Six Sigma Calculator

Related Tutorial:  Understanding defect based six sigma metrics: DPO, DPMO, PPM, DPU, Yield

Using this Pareto tool, one can visually identify the most occurring defects, most important factors or the most common problems. These “Most Important” factors are also known as “The vital few“.

Data for Pareto Analysis

Lets take the example of customer returns of toys made by a toy manufacturer. Lets start collecting data about these rejection over a fixed time period, say one month. 854 data points have been collated and grouped into 5 categories:

1. Category 1 (Example: Damaged Packaging) 155 Occurrences
2. Category 2 (Example: Color Faded) 221 Occurrences
3. Category 3 (Example: Missing Part) 33 Occurrences
4. Category 4 (Example: Missing Brochure) 112 Occurrences
5. Category 5 (Example: Wrong Toy Sent) 333 Occurrences

Now lets take the above defect categories and sort them in descending order based on the frequency of the problem occurance.

1. Category 5 → 333 Occurrences → percentage of total occurrences = 333 ÷ 854 = 38.99 %
2. Category 2 → 221 Occurrences → percentage of total occurrences = 221 ÷ 854 = 25.88 %
3. Category 1 → 155 Occurrences → percentage of total occurrences = 155 ÷ 854 = 18.15 %
4. Category 4 → 112 Occurrences → percentage of total occurrences = 112 ÷ 854 = 13.11%
5. Category 3 → 33 Occurrences → percentage of total occurrences = 33 ÷ 854 = 3.86%

Lets create an excel worksheet and place this data into it, sorted high to low. Column one is the Defect category, column 2 is the frequency of occurrence, column 3 is the percentage from the above list.

Lets create one more column and place the cumulative percentage of the frequency. Notice that for the Category 5 the cumulative frequency percentage is same as the frequency percentage. For the next category Category 2, its the some of category 5 and 2 which amounts to 38.99+ 25.88 = 64.87. For the next category in list the cumulative is 38.99+ 25.88 + 18.15 = 83.02 and so on. Finally the last category, category 3 has a cumulative frequency percentage of 100%.

The below picture shows the screenshot of the excel table that we just created. We used “Format As Table” feature to format the data into a table so we can sort on the columns easily by clicking on the arrow next to the column headings in Excel.

Next thing we need to do is create a Pareto Chart to represent the above the data graphically. Pareto chart is a bar chart with line chart overlay-ed on top of the bar chart. The bar chart represents the categories with the frequencies in descending order. We use the left Y Axis to represent the values and X Axis to represent the categories. The line chart represents the “Cumulative Frequency percentage”. We used the secondary Y axis to represent the line chart values since the scales or ranges of these values do not match.

The above chart shows all the defect categories clearly in descending order in a bar chart along with the cumulative frequency of occurrence as a line chart with values on the secondary Y axis.

How to do Pareto Analysis based on the above Pareto Chart

Pareto Analysis is analyzing the data from the above chart and finding out where the line graph crosses 80% mark on the secondary Y axis (right hand side). Then find out all the categories to the left of that point which are “vital few” or most significant factors. The remaining categories (or factors) are called “Useful Many” and they are less significant.

Vital Few = Categories with cumulative freq 80 below = Categories 5,2,1

Useful Many = Categories with cumulative freq 80 above = Categories 3,4

Pareto Chart and Analysis Summary

• Pareto Charts help finding which issues are causing most problems
• Pareto Charts are used in root cause analysis
• Pareto Charts are a decision making tool and do not contain data such as detail data analysis and costs of failure.
• Pareto analysis results in finding the efforts where it will have the most impact.
• Pareto Charts decide the order in which the issues will be addressed.

Cost of quality defects is the cost incurred due to poor quality. The cost can be measured as a percentage of lost sales. For many companies, the costs for quality defects amounts upto 40% of total sales turnover. In other words, you can improve your sales by upto 40% by simply improving your quality.

It is difficult to increase sales turnover in bad economic conditions, recession etc but one can increase the company’s profit by reducing the company’s unnecessary costs for deficient product and/or information quality.

What is Hidden factory ? The visible costs of quality versus hidden costs of quality

The cost of quality can be divided into the visible costs of quality and hidden or unmeasured costs of quality.

The visible costs of quality is a small percentage of the total costs of quality, and include:

• Scrap
• Returns
• Re-working
• Refurbishing

The hidden cost of quality

Most of the costs of poor quality are hidden from our normal quality measures. These costs of quality are often referred to as the Hidden Factory. This includes:

• Unhappy customers
• Schedule interruptions
• Fire Fighting
• Unnecessary Procedures
• Equipment Failures
• Extra Operations such as touch ups and trimming
• Distracted Engineers
• Expediting time
• Poorly performing product
• Extra inspection and testing
• Wasted materials and energy
• Sorting
• Extra inventory
• Unexplained budget variations
• Missed shipments
• Complaint Investigation Cost

Many companies only work on eliminating the visible costs. They usually miss the hidden ones. The hidden costs of quality defects are often hidden as an overhead cost which is smoothed over or thrown together with other costs, which means that the cost of the quality defect is difficult to identify. In 1977, the quality guru Armand Feigenbaum estimated the cost within the hidden factory can be 10% to 40% of total company effort. Many companies do not know where quality defects originate, nor how to identify them. Systematically focusing on identifying and eliminating visible as well as hidden costs for quality defects can give big results for relatively little effort.

What is COPQ

The term Cost Of Poor Quality (COPQ) is also used to represent the above two costs. The COPQ can be estimated by multiplying the number of defects per period of time by the average unit cost to fix a defect (labour and materials). Such a benign calculation however omits costs such as loss of goodwill and loss of competitiveness, and other matters such as warranty costs and legal damages.

Fishbone diagram is a analysis tool to provide systematic way of understanding effects and the causes that create those effect. The design of the diagram looks like the skeleton of a fish hence, it is referred to as the fishbone diagram.

Dr. Kaoru Ishikawa, a Japanese quality control statistician, invented the fishbone diagram. Also referred to as the Ishikawa diagram. Also fishbone is referred to as a cause-and-effect diagram.

Fishbone diagram is a great value in assisting teams in categorizing the many potential causes of problems or issues in a systematic way and helps identifying root causes.

A fishbone diagram be used when:

• The team needs to study a problem to determine the root cause
• Want to study all the possible reasons why a process is having difficulties, problems, or breakdowns in the initial stages of the process.
• Need to identify areas for data collection
• To study why a process is not performing properly and/or producing the expected results

Creating a Fishbone Diagram

1. Draw a fishbone diagram
2. List the problem/issue to be studied in the head of the fish
3. Label each bone of the fish. The major categories typically used are:
   • The 6 M’s: Methods, Machines, Materials, Manpower, Measurement, Management
   • The 4 P’s: Place, Procedure, People, Policies
   • The 4 S’s: Surroundings, Suppliers, Systems, Skills
4. Repeat this procedure with each factor under the category to produce sub-factors. Continue asking, “Why is this happening?” and put additional segments each factor and subsequently under each sub-factor.
5. Continue until you no longer get useful information as you ask, “Why is that happening?”
6. Analyze the results of the fishbone after team members agree that an adequate amount of detail has been provided under each major category. Do this by looking for those items that appear in more than one category. These become the ‘most likely causes”.
7. For those items identified as the “most likely causes”, the team should reach consensus on listing those items in priority order with the first item being the most probable” cause.