Unit 2

The Seven Quality Control (QC) Tools are a set of graphical and statistical techniques used in
quality management and process improvement. Each tool serves a specific purpose in
identifying and solving quality-related issues.

Flowchart: Flowcharts are graphical representations of a process, illustrating the sequence of

steps or activities involved. They help visualize and understand the process, identify
bottlenecks, and uncover opportunities for improvement.

Check Sheet: Check sheets are simple data collection forms or templates used to record and
categorize data or observations. They help in systematically collecting data and spotting trends
or patterns.

Histogram: A histogram is a graphical representation of data that displays the distribution and
frequency of values in a dataset. It provides a visual representation of data variations and can
be used to identify trends and potential issues.

Pareto Chart: A Pareto chart is a specific type of bar chart that prioritizes issues or factors
based on their significance or frequency. It follows the Pareto principle, also known as the 80/20
rule, which suggests that a significant portion of problems often comes from a small number of
causes.

Cause-and-Effect Diagram (Fishbone or Ishikawa Diagram): This tool is used to identify and
analyze the potential causes of a specific problem or issue. It resembles a fishbone, with
branches representing different categories of potential causes, helping teams systematically
investigate root causes.

Scatter Diagram: Scatter diagrams are used to visualize the relationship between two variables
or factors. They help identify correlations, patterns, or trends in data, which can be valuable for
root cause analysis and decision-making.

Control Chart: Control charts are used for monitoring and controlling processes over time. They
display data points, such as measurements or quality indicators, along with control limits.
Control charts help distinguish between normal process variations and significant deviations that
require corrective action.

These seven QC tools are often used individually or in combination to investigate issues,
identify root causes, and make informed decisions to enhance the quality of products and
processes.
A Cause and Effect Diagram, also known as a Fishbone Diagram or Ishikawa Diagram, is a
visual tool used to analyze and categorize the potential causes of a specific problem or defect.
The diagram resembles a fishbone, with the "head" representing the problem or effect, and the
"bones" branching out from it representing different categories or groups of potential causes. It
is particularly useful for identifying the root causes of issues in a structured and organized
manner.

Use a Cause and Effect Diagram in the following situations:

● Problem Solving: When you need to identify the root causes of a problem or defect to
implement effective solutions.
● Quality Improvement: To investigate quality-related issues, defects, or variations in a
process.
● Brainstorming: As a tool for collaborative brainstorming sessions to explore potential
causes of a problem.

Steps to create and use a Cause and Effect Diagram effectively:

Define the Problem (Effect): Clearly state the problem or defect you want to investigate. Write it
at the "head" of the fishbone diagram.

Identify Categories (Bones): Determine the main categories or groups of potential causes that
could contribute to the problem. These categories can vary depending on the specific issue but
often include factors like people, processes, equipment, materials, environment, and
management.

Brainstorm Causes: Within each category, conduct a brainstorming session with your team to
identify potential causes or factors that could be contributing to the problem. Write these causes
as branches extending from the respective category.

Analyze and Prioritize Causes: After brainstorming, review and analyze the potential causes.
Group similar or related causes together, and prioritize them based on their relevance and
potential impact.

Identify Root Causes: Dig deeper into each potential cause to identify the root causes—these
are the fundamental reasons behind the issue. Use tools like the "5 Whys" to drill down to the
root cause.

Take Action: Develop and implement solutions or countermeasures based on the identified root
causes. Assign responsibilities and track progres.
SIPOC Diagrams:

● Supplier - The provider of inputs into a process

● Input - Materials, information and other resources needed to complete a process
● Process - Structured steps used to convert inputs into outputs
● Outputs - Products or services resulting from the process
● Customer - Recipient of the outputs

An Example - A lemonade stand

● Supplier : Grocery store, home store, customer requests
● Inputs : Lemon juice, water, sugar, ice, cups, stirring spoon, large pitcher, wood from
home store, money jar, people to operate stand
● Process : Construct lemonade stand, combine ingredients to make lemonade in
pitcher, take customer orders, pour lemonade from pitcher to cup
● Outputs : Chilled glass of lemonade, money placed in jar
● Customer : Thirsty pedestrians

Start by giving the process a clear and concise name or title. This helps in defining the scope of
the process.

Clearly identify the starting point (where the process begins) and the ending point (where the
process ends).

List the main steps or stages of the process. Keep this list relatively high-level, typically between
four to eight main steps.

Identify the primary outputs or results of the process. Normally, this list includes the three or four
most significant outputs, even if the process generates more.

Specify who the customers of the process are. Customers can be internal (within the
organization) or external (outside the organization).

Identify the main inputs required for the process to function. Typically, list one to four primary
inputs that are essential for the process to produce the desired outputs.

Specify who supplies the inputs to the process. These suppliers could be internal or external to
the organization, depending on the nature of the process.

By following these seven steps, you'll create a SIPOC diagram that provides a structured and
holistic view of the process, its inputs, outputs, customers, and suppliers.
CTQ Tree:

A Critical to Quality (CTQ) tree is a visual tool used in Six Sigma and quality management to
identify and prioritize the critical factors that directly impact the quality of a product or service.It
is a hierarchical representation that breaks down high-level quality objectives into specific,
measurable, and critical parameters or requirements.

Creating a CTQ (Critical to Quality) tree involves a structured process to break down customer
needs into quality drivers and measurable performance requirements.

Step 1: Identify Your Customers' Critical Needs:

Start by identifying the critical needs of your customers related to your product or service..
Conduct surveys, questionnaires, focus groups, and gather customer data to understand their
needs.

Step 2: Identify Quality Drivers:

For each critical need identified in Step 1, determine the specific quality drivers that are
essential for meeting those needs. Quality drivers are the factors that customers use to evaluate
the quality of your product or service.

Step 3: Identify Performance Requirements:

Once you've identified the quality drivers, define the minimum performance requirements that
need to be met for each driver. Consider your organization's resources and technology
capabilities in determining these requirements.

Jesse is launching a store that sells baby clothing. After speaking with potential customers, one
of the critical needs she identifies is "Good Customer Service." So she uses a CTQ Tree to
create a list of measurable performance requirements that will help her to achieve this.