1. Chapter 10
Quality Improvement

2. Traditional Economic Model of Quality of Conformance
Total cost
Cost due to nonconformance
Cost of quality assurance
100%
“optimal level” of quality

3. Modern Economic Model of Quality of Conformance
Total cost
Cost due to nonconformance
Cost of quality assurance
100%

4. Problem Solving
Problem: any deviation between what “should be” and what “is” that is important enough to need correcting
Structured
Semistructured
Ill-structured
Problem Solving: the activity associated with changing the state of what “is” to what “should be”

5. Quality Problem Types Conformance problems
Unstructured performance problems
Efficiency problems
Product design problems
Process design problems

6. Problem Solving Process
Redefining and analyzing the problem
Generating ideas
Evaluating and
selecting ideas
Implementing ideas

7. The Deming Cycle
Act
Plan
Study Do

8. Juran’s Improvement Program
Proof of the need
Project identification
Organization for breakthrough
Diagnostic journey
Remedial journey
Holding the gains

9. Bethesda Hospital Model
Start
Review
current
situation
Describe
process
Explore
cause theories
Collect and
analyze data
Improvement?
Generate solutions
Plan Do
Check
Improvement?
Act no no
yes
yes

10. Crosby Quality Improvement Program
Management commitment
Quality improvement team
Quality measurement
Cost of quality evaluation
Quality awareness
Corrective action
Zero defect committee
Supervisor training
Zero defects day
Goal setting
Error cause removal
Recognition
Quality councils
Do it over again

11. Creative Problem Solving
Mess Finding – identify symptoms
Fact Finding – gather data; operational definitions
Problem Finding – find the root cause
Idea Finding – brainstorming
Solution Finding – evaluate ideas and proposals
Implementation – make the solution work

12. Six-Sigma Quality
Ensuring that process variation is half the design tolerance (Cp = 2.0) while allowing the mean to shift as much as 1.5 standard deviations.

13. Six-Sigma Metrics
Defects per unit (DPU) = number of defects discovered  number of units produced
Defects per million opportunities (dpmo) = DPU  1,000,000  opportunities for error

14. k-Sigma Quality Levels
Six sigma results in at most 3.4 defects per million opportunities

15. Six-Sigma Implementation
Emphasize dpmo as a standard metric
Provide extensive training
Focus on on corporate sponsor support
Create qualified process improvement experts
Ensure identification of appropriate metrics
Set stretch objectives

16. GE’s Six-Sigma Problem Solving Approach
Define
Measure
Analyze
Improve
Control
DMAIC

17. Tools for Six-Sigma and Quality Improvement
Elementary statistics
Advanced statistics
Product design and reliability
Measurement
Process control
Process improvement
Implementation and teamwork

18. The Seven QC Tools Flowcharts Check sheets Histograms
Cause-and-effect diagrams
Pareto diagrams
Scatter diagrams
Control charts

19. Flowcharts
Shows unexpected complexity, problem areas, redundancy, unnecessary loops, and where simplification may be possible
Compares and contrasts actual versus ideal flow of a process
Allows a team to reach agreement on process steps and identify activities that may impact performance
Serves as a training tool

20. Run Chart
Monitors performance of one or more processes over time to detect trends, shifts, or cycles
Allows a team to compare performance before and after implementation of a solution to measure its impact
Focuses attention on truly vital changes in the process
* * *
* * *

21. Control Chart
Focuses attention on detecting and monitoring process variation over time
Distinguishes special from common causes of variation
Serves as a tool for on-going control
Provides a common language for discussion process performance
* * *
* * *

22. Check Sheet Creates easy-to-understand data
Builds, with each observation, a clearer picture of the facts
Forces agreement o the definition of each condition or event of interest
Makes patterns in the data become
obvious quickly xx
xxxxxx x

23. Pareto Diagram
Helps a team focus on causes that have the greatest impact
Displays the relative importance of problems in a simple visual format
Helps prevent “shifting the problem” where the solution removes some causes but worsens others

24. Histogram
Displays large amounts of data that are difficult to interpret in tabular form
Shows centering, variation, and shape
Illustrates the underlying distribution of the data
Provides useful information for predicting future performance
Helps to answer the question “Is the process capable of meeting requirements?

25. Cause and Effect Diagram
Enables a team to focus on the content of a problem, not on the history of the problem or differing personal interests of team members
Creates a snapshot of collective knowledge and consensus of a team; builds support for solutions
Focuses the team on causes, not symptoms
Effect
Cause

26. Scatter Diagram
Supplies the data to confirm a hypothesis that two variables are related
Provides both a visual and statistical means to test the strength of a relationship
Provides a good follow-up to cause and effect diagrams *
* *
* *

27. Poka-Yoke (Mistake-Proofing)
An approach for mistake-proofing processes using automatic devices or methods to avoid simple human or machine error, such as forgetfulness, misunderstanding, errors in identification, lack of experience, absentmindedness, delays,
or malfunctions

28. Poka-Yoke Examples (from John Grout’s Poka-Yoke Page)