Customer CTQs – Defining Defect, Unit and Opportunity

In order for any process capability to accurately be calculated, one must properly define and quantify the process defect, unit and opportunity of a customer CTQ. This article defines the three terms, as well as provides examples.

By Kerri Simon

In order for any process capability to accurately be calculated, one must properly define and quantify the process defect, unit and opportunity. Every process should have definitions for defect, unit and opportunity. This article will define the defects, units and opportunities, as well as provide examples.

Start With The Customer
Before you can define your process defects, units and opportunities, you need to understand the needs of your customers. Voice of the Customer (Customer Needs, eSurveys, Focus Groups, Surveys) is the process of gathering customer comments/quotes and translating them into issues and specifications. From these comments, issues and specifications come the customer CTQ (Critical To Quality) – a product or service characteristic that must be met to satisfy a customer specification or requirement.

Handpicked Content :   Understanding Process Sigma Level

Define Your Product/Service Defects
A defect is defined as any part of a product or service that:

  • does not meet customer specifications or requirements, or
  • causes customer dissatisfaction, or
  • does not fulfill the functional or physical requirements.

It should be noted that the term customer refers to both internal and external customers.

Define Your Product/Service Units
A unit is something that can be quantified by a customer. It is a measurable and observable output of your business process. It may manifest itself as a physical unit or, if a service, it may have specific start and stop points.

Define Your Product/Service Opportunities
Simply stated, opportunities are the total number of chances per unit to have a defect. Each opportunity must be independent of other opportunities and, like a unit, must be measurable and observable. The final requirement of an opportunity is that it directly relates to the customer CTQ (see Start With The Customer above). The total count of opportunities indicates the complexity of a product or service.

Handpicked Content :   Managing for Results Using a Lean Six Sigma Strategy - A Conversation with… Nick Brownrigg, Chief Executive Officer of Masterlease

CTQ Examples Including Defect, Unit and Opportunity

Area: Call Center
Customer Quote: ‘I consistently wait too long to speak to a representative.’
CTQ Name: Representative Responsiveness
CTQ Measure: Time on hold (seconds)
CTQ Specification: Less than 60 seconds from call connection to the automated response system
Defect: Calls with hold time equal and greater than 60 seconds
Unit: Call
Opportunity: 1 per call

Sigma CalculatorCalculate Your Sigma (Plug in the values below to calculate Sigma)
Defects: 263 calls
Units: 21,501 calls
Opportunities: 1 per call
Sigma: 3.75

Area: Book Publisher
Customer Quote: ‘I can’t stand typos in books I purchase.’
CTQ Name: Typographic Quality
CTQ Measure: Number of typographical mistakes
CTQ Specification: Zero typographical mistakes
Defect: Any typographical mistakes
Unit: A word
Opportunity: Words per book

Sigma CalculatorCalculate Your Sigma (Plug in the values below to calculate Sigma)
Defects: 2 typographical mistakes
Units: 100,000 (500 words/page x 200 pages/book)
Opportunities: 1 per word
Sigma: 5.61
Handpicked Content :   Should You Calculate Your Process Sigma?

Area: Printed Circuit Board Manufacturing
Customer Quote: ‘Boards must work when I plug them in.’
CTQ Name: Board Functionality
CTQ Measure: Non-functioning or improperly functioning boards
CTQ Specification: All boards function properly (a board wil not function properly if any individual component is bad)
Defect: Any non-functioning or improperly functioning board
Unit: A board
Opportunity: Total number of parts plus solder points

Sigma CalculatorCalculate Your Sigma (Plug in the values below to calculate Sigma)
Defects: 18 boards
Units: 1,000 boards
Opportunities: 58 (1 board + 13 resistors + 4 capacitors + 2 diodes + 38 solder points)
Sigma: 4.92

You Might Also Like

Comments 5

  1. Sparrowhawk

    I conduct daily quality audits in an assembly environment. There are 17 line items on my audit; therefore, there are 17 opportunities per sample. I’m unsure whether I should record defects at the line item level or the sample level. In other words, is the entire sample considered 1 defect if 14 criteria pass and 3 fail? Or do I record the 3 failures independently?

    My DPMO formula: (defects/17)*1,000,000

    I need to define “defects” …samples or line items?

  2. Rohit Gadhoke

    You are confused between defect and defective primalrly. I assume in the above example that if 1 line item will impact the entire unit in such a scenario

    Defects: 40 ( In the entire assembly)
    Opporturnities = 17
    DPMO: 2353

    I hope you can calculate the sigma level

  3. Rajeev Kumar 9268710994

    Defects – which is not meet the customer requirement ,
    if one parts have three problem then we says that is 3 defects
    defective is one

  4. Vaughn Machristie

    Very well written and informative…!!!

  5. vishal gaba

    In a quality checking 10 boxes controlling 200 packets of royal candies it was found that 30,34,32,24,32,28,2234,40,44 packets were defective draw the suitable control chart UCL LCL control limit


Leave a Reply