What is the definition of "special cause variation"?
A source of variation that causes a fundamental change in a process. Special cause variation signals a change in a process and can be traced back to a single source.

Learn more about special cause variation in the class Intro to Six Sigma 170 below.


Quality Training


Class Information
Tooling U-SME classes are offered at the beginner, intermediate, and advanced levels. The typical class consists of 12 to 25 lessons and will take approximately one hour to complete.
Class Name:Intro to Six Sigma 170
Description:This class covers the basic concepts of Six Sigma, including data analysis, types of variation, common and special causes, the roles of Six Sigma team members, and the DMAIC method.
Prerequisites: none
Difficulty:Beginner
Number of Lessons:16
Language:English, Spanish
 
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Class Outline
  • Objectives
  • What Is Six Sigma?
  • The Six Sigma History and Makeup
  • Getting Started
  • Six Sigma Roles and Responsibilities
  • 5 Ms and 1 P
  • Root Cause Analysis
  • Variation
  • Importance of Data
  • Types of Data
  • Gathering Data
  • Data Analysis Tools: Discrete Data
  • Data Analysis Tools: Continuous Data
  • Six Sigma Process Improvement Method: DMAIC
  • Implementing Six Sigma
  • Summary
  
Class Objectives
  • Define Six Sigma.
  • Describe the origins of Six Sigma practices.
  • Identify the criteria for choosing Six Sigma project targets.
  • Identify the roles and responsibilities of Six Sigma team members.
  • Identify common factors that lead to process problems.
  • Define root cause analysis.
  • Define common cause variation.
  • Define special cause variation.
  • Describe the importance of data for Six Sigma projects.
  • Distinguish between discrete and continuous data.
  • Compare common inspection methods with the resulting data.
  • Identify decision-making tools used to analyze discrete data.
  • Identify decision-making tools used to analyze continuous data.
  • Identify the steps in the DMAIC process improvement method.
  • Describe how lean practices are incorporated into Six Sigma initiatives.

Class Vocabulary

Vocabulary TermDefinition
5 Ms and 1 P An expression identifying the six major factors most likely to be the source of problems. These factors are machines, materials, methods, Mother Nature, measurement, and people.
attribute data Data that represents an individual characteristic or a count. Also known as discrete data, attribute data cannot be added to or subtracted from other attribute data.
bell-shaped curve A graph of variable data characterized by a high center, tapered sides, and bell-flared edges. A bell-shaped curve reflects conditions that exhibit natural variation.
black belt A Six Sigma practitioner with the most training who acts as the project leader. Black belts work full time on projects and coach lower-level team members.
champion A Six Sigma designation for an executive or manager within a company who can get things done for the team. Champions make sure that the team has necessary resources.
charter A document that serves as a problem statement defining the Six Sigma project target.
common cause variation A source of variation that is normal and expected. Common cause variation is predictable and cannot be traced back to a single source.
continuous data Data that can be measured on a scale and compared with other data. Also known as variable data, it can be added to or subtracted from other continuous data.
continuous improvement The belief that an organization must constantly measure the effectiveness of its processes and strive to meet more difficult objectives to satisfy customers.
critical to quality Specific, measurable characteristics of a product or process that are identified by customers as necessary for their satisfaction.
cycle time The actual time it takes to perform a task and forward it to the next step.
data Factual information, usually in the form of numbers, that is used for analysis and problem solving.
discrete data Data that represents an individual characteristic or a count. Also known as attribute data, discrete data cannot be added to or subtracted from other discrete data.
DMAIC Six Sigma's five steps for process improvement. DMAIC stands for define, measure, analyze, improve, and control.
external customer An outside organization or individual that receives a product or service from the company.
finish grinding An abrasive process that improves the surface of the part.
frequency distribution A systematic method of showing the number of occurrences of observational data in order from least to greatest. Frequency distributions best represent continuous data.
go-no go gage A measuring instrument that determines whether a part feature simply fits or does not fit and therefore passes or fails inspection. No effort is made to determine the exact degree of error.
green belt A team member trained in Six Sigma who spends about 20% of his or her time on Six Sigma projects and about 80% on regular duties.
internal customer A department or individual within the company that relies on others to satisfy the external customer. In a multi-step process, the next step in the process is always the internal customer.
ISO 9000 A standard published by the International Organization for Standardization that lists requirements for the creation and implementation of an effective quality management system.
just-in-time manufacturing An approach to production and distribution that emphasizes flexible processes and reduced inventories to decrease costs and improve responsiveness.
lean manufacturing An approach to manufacturing that seeks to improve product quality and productivity, reduce cost, and eliminate waste.
master black belt A hands-on Six-Sigma practitioner who works closely with other members to set and carry out project goals. Master black belts work full time on projects and coach lower-level team members.
non-value added Activities that do not contribute to the product or the process and should therefore be eliminated. Non-value added steps are waste.
Pareto chart A bar chart that shows the order of the most frequently occurring errors or sources of errors. Pareto charts best represent discrete data.
Pie chart A circular chart that is cut into slices that represent the frequency of the collected data. The bigger the slice, the higher the number or percentage. Pie charts best represent discrete data.
process mapping A graphical method of capturing the steps of a process. Process mapping can be performed before and after a process is improved.
process owner A temporary designation for the person responsible for process design and performance. Green belts are sometimes considered process owners.
quality management A process improvement method that focuses on increasing customer satisfaction at a reasonable cost to the company.
root cause analysis A study undertaken to find the first or underlying cause of a problem. Root cause analysis involves the collection and study of data to determine a true cause to a problem.
run chart A graphic representation of process performance data tracked over time. Run charts best represent continuous data.
Six Sigma A management philosophy and process improvement method that uses data to identify problems and point to improvements. Six Sigma's goal is to reduce the number of defects to less than 3.4 defects per million opportunities, which is near perfection.
special cause variation A source of variation that causes a fundamental change in a process. Special cause variation signals a change in a process and can be traced back to a single source.
statistical process control The use of statistics and control charts to measure key quality characteristics and control how the related process behaves. SPC separates special causes of variation from common causes.
total quality management A management method popular in the 1980s and 1990s that was based on a list of improvement philosophies. The purpose was to bring about company-wide change and continuous improvement.
value-added Any part of the production process that improves the product for the customer.
variable data Data that can be measured on a scale and compared with other data. Also known as continuous data, it can be added to or subtracted from other variable data.
variation A difference between two or more similar things.
waste Any thing or process that does not add value to a product. Waste is often tied to special causes of variation.
yellow belt A designation for other staff members who help with Six Sigma projects.