CTQs

Critical To Quality - CTQs (Critical to Quality) are the key measurable characteristics of a product or process whose performance standards or specification limits must be met in order to satisfy the customer.

CTQs align improvement or design efforts with customer requirements.

CTQs represent the product or service characteristics that are defined by the customer (internal or external). They may include the upper and lower specification limits or any other factors related to the product or service.

A CTQ usually must be interpreted from a qualitative customer statement to an actionable, quantitative business specification.To put it in layman's terms, CTQs are what the customer expects of a product... the spoken needs of the customer. The customer may often express this in plain English, but it is up to us to convert them to measurable terms using tools such as DFMEA, etc.

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. Every process should have definitions for defect, unit and opportunity.

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.

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
• 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. The total count of opportunities indicates the complexity of a product or service.

CTQ Examples Including Defect, Unit and Opportunity

Area: Call CenterCustomer
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

Calculate Your Sigma
Defects: 263 calls
Units: 21,501 calls
Opportunities: 1 per call
Sigma: 3.75

Area: Book PublisherCustomer
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

Calculate Your Sigma
Defects: 2 typographical mistakes
Units: 100,000 (500 words/page x 200 pages/book)
Opportunities: 1 per word
Sigma: 5.61