Quality In Process Control Charts

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Chapter 1  :  About the importance of quality and of 
the methods to achieve it 
 
1.1 Introduction: a complete definition of Quality 
 
What does the word "Quality" mean? If we pause for a while before 
replying, we realize how it is hard to find a sole answer to this 
question. Each of us keeps in mind its own definition of quality and 
also great masters as W. Edwards Deming and Joseph M. Juran have 
expressed this concept in different ways. 
In his book "Quality planning and analysis", Juran observes that 
the basic meaning of the word quality is "fitness for use" ; on the 
other hand, in his book "Out of the crisis", Deming notices that at 
the question "What is quality?" one must reply that: "Quality can be 
defined only in terms of the agent", where the agent, also indicated 
as the "judge of quality", from time to time could be the production 
worker, the plant manager, the purchaser, the consumer and so on. 
In his turn, Deming, in these observations, has been influenced by 
another great master, Walter A. Shewhart, who devoted a whole 
chapter of his book "Economic control of quality of manufactured 
product" to the matter of the definition of quality. The 
introductory note of this chapter states that: "When we analyze our 
conception of quality, we find that the term is used in several 
different ways. Hence, it is essential that we decide, first of all, 
whether the discussion is to be limited to a particular concept of 
quality, or to be so framed as to include the essential element in 
each of the numerous conceptions." [Shewhart, 1931]  
As anyone can easily understand, we need a definition which is 
both complete and incontrovertible, or in other words, a definition 
of quality that could apply to any product, service or other entity 
we are dealing with. One of the most complete definitions ever found 
in "quality literature" is certainly that contrived by Fausto 
Galetto in his book "Qualità: alcuni metodi statitici da manager", 
according which:  
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"Quality 
is the set of characteristics of a system 
 that makes it able to satisfy the needs of the Customer, 
 of the User and of the Society."  
[Galetto, 1985] 
 
The author gives an explanation of the concept and definition of 
quality that fully justifies our choice of electing it as one of the 
the most complete about the matter: the term system is used to 
indicate both a product, just like a car or a television set, and a 
service, which is carried out through a process of relationships 
that provide a certain output. Moreover, system may be interpreted 
as any set of mental and physical activities, correlated each other, 
which provide an output that from time to time may be a product, a 
service, a method, an idea and so on.    
The definition of quality just presented has to be considered 
complete also from another point of view: the subjects involved are 
not only the Customer and the User, but also the Society. This means 
that all these products or services that could be bad for the health 
of workers or for the environment must not be considered quality 
product. 
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1.2 Quality and competition 
 
Saying that quality is important may appear obvious, but it would 
be a mistaken judgement to understimate this fact: as Juran properly 
observes, quality is a "weapon of competition".  
Quality, together with other factors such as, for example, price 
and innovation, represents an element of fundamental importance for 
companies: it warrants them a very competitive position in business.       
Competition is of fundamental importance not only for the survival 
of companies, but also for Society: it does not only allows 
companies to stay in business, it also provides jobs and so it 
benefits Society. 
With regard to this important role of quality in companies, 
Galetto contrived the so-called "Competitiveness Tetrahedron" 
reported in figure 1.1, where every edge represents one of the 
factors which allows companies to be competitive: Price, Innovation, 
Response Speed, Profitability, Image and Quality of course.  
 
 
Figure 1.1 : Competitiveness Tetrahedron [Galetto, 1996] 
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As anyone can easily guess, these factors must complement each 
other and are all equally important for company survival: Customer's 
choices are striclty influenced by them and it could cost too much 
to companies disregarding this fact.     
 
1.3 Quality and productivity 
 
Nowadays, in several companies, it is common opinion that quality 
and production are incompatible and that when one improves the other 
decreases.  
Actually, this opinion seems to be spoiled by prejudice against 
the role of quality department in companies: in fact quality, when 
it is real, entails less rework, less waste and less problems both 
for the Customer and the company. 
With regard to the relationship between quality and productivity, 
Deming observes that: "Improvement of quality transfers waste of 
man-hours and of machine-time into the manufacture of good product 
and better service. The result is a chain reaction - lower costs, 
better competitive position, happier people on the job, jobs, and 
more jobs." [Deming, 2000]    
The chain reaction the author refers to is that shown in figure 
1.2: it was on the blackboard of every meeting with top managament 
in Japan
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 from July 1950 onward. 
 
 
Figure 1.2 : Chain reaction [Deming, 2000] 
                                                          
1
 We have to remember that W. E. Deming is the internationally renowned consultant 
in quality and productivity management whose work gave a fundamental contribution 
to Japanese industry. 
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But improvement of quality is not so easy as it may appear: first of 
all, this aim requires all company's functions to be involved in 
achieving it; second, it requires management to be aware of the 
value of quality and of its fundamental role for company's 
economics; but, above all, quality improvement and problem 
prevention need competent people and appropriate methods for 
achieving it: what companies really need is developing the "culture 
of quality". 
These aspects are so important that it is worth devoting them the 
right space: for this reason, we will analyze them in detail on next 
sections. 
 
1.4 Quality: cost or investment? 
 
Once reached the awareness that quality improvement implies less 
defects, less reworks, less waste and so on, how can we question the 
economical role played by quality in companies? 
As rightly observed by Deming, "the cost of rework is only part of 
the cost of poor quality. Poor quality begets poor quality and 
lowers productivity all along the line, and some of the faulty 
product goes out the door, into the hands of the customer. An 
unhappy customer tells his friends. The multiplying effect of an 
unhappy customer is one of those unknown and unknownable figures, 
and likewise for the multiplying effect of a happy customer, who 
brings in business." [Deming, 2000] 
Poor quality (or disquality, as named by Galetto) does cost: 
defects, waste, reworks, mistakes are not free and companies must 
pay for them, since someone must correct them: would not it be 
better to avoid them, to understand in advance where matters lie 
concealed, to prevent them?  
This question is not a rhetorical one. Companies need quality to 
stay in business, but quality is a matter of culture: anyone must 
learn how to achieve it, must realize that commitment on quality is 
not a waste of time and money, and above all, must understand that 
quality, when it is real, is no more a cost than an investment. 
Actually, saying that quality is free, is not completely true: 
people who works on quality must be aware of the heavy 
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responsibility by which they are burdened. Working on quality means  
knowledge of methods fit for taking decisions that will affect 
company's destiny, its credibility and reputation; the consequences 
of wrong decisions could be very costly for companies and transform 
investment on quality into costs of disquality. Quality requires 
people to commit themselves to achieve it, to spend time in learning 
the proper methods (which must be methods of quality) that allow 
them taking the right decisions, to understand the damaging effects 
of wrong methods claimed as the "panacea for all the problems".  
In other words quality does cost in terms of intellectual efforts 
and commitment that people must lavish to achieve it: from this 
point of view quality is very expensive and this justifies the need 
of competent people and proper methods to work on it. 
Unfortunately, very often these aspects are disregarded by 
companies, which understimate the effects of decisions taken by 
people who know very little about quality and are influenced by 
misleading methods.  
 
1.5 Quality: who must achieve it? 
 
As indicated in the previous section, quality can be achieved only 
by competent people, namely by good management, as for company's 
survival, and by good teachers, as for education of beginners.  
As clearly proved by several scholars, as well as Deming, Crosby, 
Feigenbaum, Galetto and Nelson, quality in companies is essentially 
a matter related to management: "Managers have the responsibility of 
major decisions in a company and the soundness of their decisions 
affects the quality of the products and the satisfaction of 
customer's needs. In order to make sound decisions managers have to 
be aware of the consequences (which is prevention using management 
by if... then... else (MBITE)) of their decisions; in relation to 
quality matters, managers have to commit themselves to ensuring that 
the concepts and disciplines associated with quality will be 
introduced into the developments programmes of the company." 
[Galetto, 1999] 
The responsibility for quality improvement in companies lies with 
managers: they have to make the right decisions on the basis of few 
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data. For this reason, they have a great responsibility towards the 
whole company, they must be aware that methods used to take 
decisions are not all equally good, and, above all, they must be 
able to discriminate between sound methods and misleading ones. The 
matter is that very often managers do not realize and recognize 
their responsibility and are persuaded the most of disquality 
problems to be ascribable to production workers: this is a wrong way 
of thinking and acting. 
Even when management is aware of its responsibility, the methods 
used to take decisions are often bad, and no one takes care of 
verifying their soundness: this is another wrong way of thinking and 
acting. 
As for the education of beginners, things are equally serious: 
several courses on quality do not devote the right space to the 
analysis of good methods; quality reviews are full of articles, 
written by teachers, which praise misleading methods; consultants 
and so-called experts are often full of hot air and take advantage 
of selling methods which have little or nothing to do with quality. 
"Awakening to the need for quality, and with no idea what quality 
means and how to achieve it, American management have resorted to 
mass assemblies for crash courses in statistical methods, employing 
hacks for teachers, being unable to discriminate between competence 
and ignorance. The result is that hundreds of people are learning 
what is wrong." [Deming, 2000] 
Again we must point out that managers, as well as teachers and 
consultants, are burdened by heavy responsibility: future of 
companies is in their hands, they cannot understimate the 
consequences of their decisions, they must be rational managers. 
With regard to the role managers have to play, F. Galetto, deviser 
of the adjective "rational" related to manager, observes: "Managers 
are decision-makers and therefore need tools for thinking in 
decision-making in order to be rational managers: to recognize 
problems, collect information, set priorities accurately, find 
causes, consider all factors and other people's views, consider 
alternative courses of actions, consider consequences and sequels to 
troubleshoot the future, consider risk to any choice, etc. 
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To make full use of the thinking ability of people there is a 
basic approach, the if... then... else... (ITE) approach to 
decisions: 
every time a manager has to make a step in the decision process, 
he/she must ask him/herself 
 
If      I do this 
Then    I shall have consequence 
Else    I shall have this other consequence 
 
ITE is an integrated, holistic approach that release intellectual 
resources that have been hidden, unused or underused, opening 
channels of communication among people. This is the fundamental 
basis for prevention. MBITE is the acronym devised to remind 
managers of their obligations for prevention and long-term 
commitment." [Galetto, 1999]      
These few lines highlight an important aspect: managers must 
commit themselves in taking the right decisions making use of their 
thinking skills to deduce logical consequences from the available 
information and facts, the proper methods and a sound theory; in 
other words they must be intellectually honest and aim at the 
achievement of the profound knowledge (see Deming) which would 
warrant companies to stay in business. 
Another issue clearly pointed out by Galetto is the importance of 
prevention; as we will see later, prevention is the core of quality: 
management must understand that corrective actions are completely 
different from preventive ones, and that great care must be taken in 
order to chose methods fit for dealing with problems prevention. 
Again the central point of the matter is represented by the choice 
of methods for quality which can lead to the right decisions. 
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1.6 Quality of methods for quality 
 
So far the importance of good methods for quality has been 
repeatedly pointed out: we did not mean to bore the reader, but 
rather to get him acquainted with the damaging effects that wrong 
methods can give rise to.   
When managers use a particular method in order to make decisions 
on the basis of available data, they must understand whether the 
method itself is sound or not; a bad method can lead only to wrong 
decisions, wrong decisions may have heavy consequences for the 
credibility and reputation of company and for the future of its 
workers: nowadays, companies cannot afford the luxury of making 
mistakes, the destiny of lots of people is in their hands.   
The use of misleading methods, together with the obvious effects 
on company's reputation, wastes time and money and, as it is well-
known, resources are limited, no one should waste them. 
But how can we discriminate between a good method and a bad one? 
Only Logic and Scientific Approach can provide the right route 
towards good methods. 
These few lines tell something important: only people who commit 
themselves in the analysis and research of the methods can 
understand their soundness. But understanding is not enough: they 
must be intellectually honest and avoid using bad methods, even if 
they are praised by "experts", consultants and so on.  
Since, according to the F1 principle (devised by Galetto), 
"reality does exist in spite of human beings' willingness and 
ability to recognize it", we cannot expect good outcomes from the 
application of wrong methods neither if lots of (wrong) papers are 
written to prove the contrary. 
Every method for taking decisions should be a scientific approach 
to decisions and should be analysed from the viewpoint of Logic, not 
blindly used; neglecting too long the effects of the application of 
wrong methods can lead to unpleasant consequences: these methods, 
usually easy to use and well "wrapped up" in some software packages, 
spread quickly and undermine sound "old and obsolete" methods. 
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This is what happened to Taguchi methods: the early wariness that 
received them at their appearence, with time has changed into great 
respect so that now, according to many teachers, "experts", 
consultants and so on, they are worthy of the highest praise. 
Intellectually honest people, by virtue of Logic and Scientific 
Approach, have proved the misleading outcomes provided by Taguchi 
methods, but their voice has been unheard: must we doubt someone to 
have something to gain from the spread of certain methods? Cui 
Prodest? Unfortunately, no answer will be given to these questions. 
The same remarks made with reference to the Taguchi methods, hold 
also for other methods: a look at Galetto's papers would be very 
interesting and useful since he devoted, sometimes together with his 
students, lot of time and research to the analysis of non-scientific 
methods for quality. Teachers, consultants and "experts" would learn 
a lot of things about quality of methods for quality if only they 
would test themselves out: understanding Galetto's papers could be a 
good "crash test". 
Very often, wrong methods suffer from a lack of Logic and total 
absence of statistical basis, which are fundamental for quality 
achievement and improvement: companies need competent managers who, 
making use of their knowledge and ability, can teach "statistical 
thinking" (term contrived by Deming) to other managers, engineers, 
foremen, supervisors, production workers, designers and so on. Good 
knowledge of statistics is needed in order to discover the fallacy 
of bad methods: this means that teaching pure statistical theory in 
universities, including probability theory, should be excellent and, 
consequently, should be entrusted to qualified teachers. As Deming 
states very clearly: "Teaching of beginners should be done by a 
master, not by a hack", "anyone that engages teaching by hacks 
deserves to be rooked" and "nothing takes the place of a good 
teacher". 
Managers and teachers must commit themselves in the use of sound 
methods if they want achieve and improve quality: they must analyse 
any method before using it and, above all, they must remember that 
"it is a hazard to copy. It is necessary to understand the theory of 
what one wishes to do or to make." [Deming, 2000] 
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In order to point out the importance of the quality of quality 
methods, Galetto contrived the matrix shown on figure 1.3. 
 
Figure 1.3 : Knowledge matrix [Galetto, 1999] 
"The right tools can be used if managers – as well as teachers, 
consultants, experts – use correctly the "knowledge matrix", a cell 
which represents the knowledge situation of two people who have to 
make a decision based on their knowledge. It is clear that in order 
to achieve quality, people must move to the left upper corner: both 
good knowledge and good applications are needed." [Galetto, 1999]        
It is worth noting that many good methods are available for 
working on quality, but each of them applies to different phases of 
the processes of achievement and improvement; falling in love with a 
sole method is not a good idea! 
We will clarify the role played by different good methods on the 
next section. 
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1.7 Quality methods, development cycle and prevention 
 
How does quality of products and services be achieved by managers? 
According to Deming, "the consumer is the most important part of the 
production line. Quality should be aimed at the needs of the 
consumer, present and future. 
Quality begins with the intent, which is fixed by management. The 
intent must be translate by engineers and others into plans, 
specifications, tests, production." [Deming, 2000] 
As shown on figure 1.4, quality is related to all the phases of 
the product develpment cycle: from the analysis of the needs of 
Customer, User and Society to the design, from production to the 
release of the product in the market-place. 
As we can see, many important phases, the first ones, of the 
development cycle are related to the so-called preventive actions; 
corrective actions and product improvement come only in the second 
place. This underlines the importance of prevention: if managers do 
not commit themselves in problems prevention, they assure troubles 
and high costs of disquality. It is soon clear that it is absolutely 
necessary to prevent failures, defects, flaws and mistakes before 
the product is relesead to the market-place.