Definitions

VRI Acronym Definition List

Below is a list of commonly used Lean/Six Sigma acronyms to help you navigate through our site.

CE CLT CNX CODN COPQ Cp Cpk CTC CTQ DMAIC DOE dpmo dpu FMEA FPY IMR IPO JIT KPI LCL & UCL LSL & USL MSA PF QFD ROT RPN RTY SIPOC SME SOP SPC TOC UDEUDE VOB VOC VOP WIIFM WIP

Acronym	Meaning	Definition
CE	Cause & Effect diagram	A tool for identifying the possible sources of variation for a given output or process.
CLT	Central Limit Theorem	Says that for most cases, regardless of the shape of a distribution (the parent), the distribution of sample averages (the child) drawn from this distribution will be approximately normally distributed.
CNX	Constant, Noise, Experimental	The way we partition the input variables on a cause & effect diagram. Constants require standard operating procedures.
CODN	Cost of Doing Nothing	If no process improvements were made, this is the cost, cycle time and quality you would expect your process to be.
COPQ	Cost of Poor Quality	The cost associated with scrap, rework, etc. Five main categories are: internal failure costs, external failure costs, appraisal costs, prevention costs, and opportunity costs.
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Cp	Process Capability Potential	Measures the potential capability of a process without considering centering. A Six Sigma process will have a Cp value of 2 or larger.
Cpk	Process Capability - Actual	Measures the actual capability of a process, taking into account the centering of the process. A Six Sigma process will have a Cpk value of 1.5 or larger.
CTC	Critical to Customer	Measures of performance that is critical to your customer. These can be seen on the output of an IPO Diagram.
CTQ	Critical to Quality	Measures of performance that is critical to quality of your process. These can be seen on the output of an IPO Diagram.
DMAIC	Define, Measure, Analyze, Improve, & Control	A strategy for process improvement. It involves using the right tools at the right time to answer the right questions. The 15 questions will take you through this roadmap. (see full definition)
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DOE	Design of Experiments	A systematic method for varying the inputs of a process in order to observe the corresponding changes in the output(s). The result is information on the importance and/or a model of the relationships of inputs to outputs.
dpmo	defects per million opportunities	A measure of quality for attribute data which is used for benchmarking purposes. A Six Sigma process will have no more than 3.4 dpmo.
dpu	defects per unit	A measure of quality for attribute data.
FMEA	Failure Mode and Effect Analysis	A systematic way to look at how a process or product might fail and work to identify says to prevent failures from occurring.
FPY	First Pass Yield	The proportion of units completing a process the first time with no rework, repair or replacement.
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IMR	Individual Moving Range Chart	A control chart for variable data with individual measurements (no subgroups).
IPO	Input - Process - Output diagram	A diagram for describing all activities as a process, showing the inputs (sources of variation) and outputs (measures of performance) of a process.
JIT	Just In Time	Producing a product or service Just In Time.
KPI	Key Performance Indicator	Measures of performance of your process. These can be seen on the output of an IPO Diagram.
LCL & UCL	Lower Control Limit & Upper Control Limit	Limits which are used to determine whether a process is stable. They are calculated from the data and usually set at +/- 3 standard deviations
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LSL & USL	Lower Specification Limit & Upper Specification Limit	The bounds of acceptable values for a given product or process parameter, as specified by the customer.
MSA	Measurement System Analysis	Method for partitioning the sources of variation in a process into product and measurement error.
PF	Process Flow	A flowchart listing the process steps in order.
QFD	Quality Function Deployment	A systematic process for integrating customer requirements into every aspect of the design and delivery of products and services.
ROT	Rule of Thumb	This is a short cut, not exact, but an estimate. General statements that will work most of the time.
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RPN	Risk Priority Number	In FMEA, this is the column which indicates high risk process steps or elements of a design. It is equal to Severity * Occurrence * Detection.
RTY	Rolled Throughput Yield	The likelihood of making it through all steps in the process, right the first time. It is calculated by multiplying all the process steps FPY.
SIPOC	Supplier, Input, Process, Output, Customer Diagram	This is similar to the IPO only it expands to include the suppliers to the process and the customers. This can be used to show the process Value Stream and/or a macro flow of the entire process.
SME	Subject Matter Expert	People that are experienced and experts in the process.
SOP	Standard Operating Procedure	Details on how a factor should be held constant for a process. SOPs help eliminate unnecessary variation.
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SPC	Statistical Process Control	A methodology for studying a process using control charts.
TOC	Theory of Constraints	The study of looking for where a process is constrained. Commonly called the process bottleneck.
UDE	Undesirable Effect	An effect on the process that is not desired or wanted, i.e., scrap, rework, etc.
VOB	Voice of the Business	These measures usually point to key business strategies such as cost metrics, scrap, process delays, etc.
VOC	Voice of the Customer	These are usually measured in the upper and lower specification limits from the customer.
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VOP	Voice of the Process	In continuous data, this is typically the mean and the standard deviation.
WIIFM	What's In It For Me?	Building a vested interest to all involved in the process
WIP	Work In Progress	Parts and uncompleted goods throughout the process.
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Lean Six Sigma Roadmap DMAIC Strategy

DMAIC (Define, Measure, Analyze, Improve, & Control) is an acronym that can be defined as the roadmap to process optimization and are the five phases of Six Sigma improvement. These phases lead to a team logically from defining a problem through implementing solutions linked to underlying causes, and establishing best practices to make sure the solutions stay in place.

D-M-A-I-C is structured as:

Design:

Identify and Prioritize Opportunities
Select Your Project
Define the Goals and Objectives
Form Cross functional Team
Understand Customer Requirements

Measure:

Define and Analyze the Current Process
Assess the Capability of the Measurement Process
Assess the Current Capability of the Process
Variance Reduction

Analyze:

Identify the Key Input Variables
Discover the Relationship between the Inputs and Outputs
Identify the Root Causes of the Problems

Improve:

Identify and Test the Proposed Solutions
Re-assess Capability
Implement Solution

Control:

Document Results and Return on Investment
Take Actions to Hold the Gains
Celebrate and Communicate

Resources