Autor:
Ing. Manuel Pérez Aragón
Por
considerar de sumo interés los comentarios que leerá líneas abajo,
incluimos este aporte recibido en nuestra redacción:
Apreciados
señores de www.gerenciasalud.com:
Aunque
no nos conocemos, si quiero informarle en relación al articulo mencionado,
aparecido en gerenciasalud.com que nuestro común conocido
Wilfredo Pareto jamás propuso como Gráfico el que actualmente lleva su
nombre.
El
error lo ocasionó un gran profesor mío que se llama Joseph Juran y que no
tuvo el rigor de contrastar la información que obtuvo en 1940 durante la
preparación de su libro "Quality Control Handbook" y darse
cuenta que, el autor de los denominados Gráficos de Pareto fue en realidad
M.O.Lorentz, como se puede comprobar en
Lorenz,
M.O., Methods of measuring the concentration of wealth, American Statistical
Association publication, vol. 9 (1904-1905), pp. 200-219.
Adjunto
copia del escrito de J.Juran publicado en 1984.
De
todas formas creo que a estas alturas el Gráfico de Pareto tiene pocas
posibilidades de denominarse como su autor real.
Atentamente
Manuel
Pérez Aragón
Ingeniero Industrial y Economista
Auditor de Sistemas de Gestión de Calidad
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"The Non-Pareto
Principle; Mea Culpa"
J.M. Juran
Contributing Editor
The "Pareto principle"
has by this time become deeply rooted in our industrial literature. It is a
shorthand name for the phenomenon that in any population which contributes to
a common effect, a relative few of the contributors account for the bulk of
the effect.
Years ago I gave the name
"Pareto" to this principle of the "vital few and trivial many."
On subsequent challenge, I was forced to confess that I had mistakenly applied
the wrong name to the principle.1 This confession changed nothing – the name "Pareto principle"
has continued in force, and seems destined to become a permanent label for the
phenomenon.
The matter has not stopped
with my own error. On various occasions contemporary authors, when referring
to the Pareto principle, have fabricated some embellishments and otherwise
attributed to Vilfredo Pareto additional things which he did not do. My motive
in offering the present paper is in part to minimize this tendency to
embroider the work of a distinguished Italian economist. In addition, I have
for some time felt an urge to narrate just how it came about that some early
experiences in seemingly unrelated fields (quality control, cryptanalysis,
industrial engineering, government administration, management research)
nevertheless converged to misname the Pareto principle.
It began in the mid-1920s
when as a young engineer I observed (as had many others before me) that
quality defects are unequal in frequency, i.e., when a long list of defects
was arranged in the order of frequency, a relative few of the defects
accounted for the bulk of the defectiveness. As I moved into quality
management posts in the late 1920s and the 1930s, I observed (as had many
others before me) that a similar phenomenon existed with respect to employee
absenteeism, causes of accidents, etc.
During the late 1930s I
moved out of the field of quality control to become the corporate industrial
engineer for Western Electric Company. In this capacity, one of my
responsibilities was to visit other companies to exchange experiences in
industrial engineering practices. One of the most exhilarating of these visits
was to General Motors Corporation's headquarters. There I found an uncommonly
competent team of managers facing up to the then new problems of collective
bargaining. As an incidental tool, they had put together an assortment of data
processing machinery to enable them to compute the cost of any new labor union
proposal. This they did by programming the machines and then running the (punched)
employee record cards through the program. It was an ingenious concept, and
their system was quite advanced for those days. However, the electro-magnetic
machinery then in use took hours and even days to process those hundreds of
thousands of cards, so that the managers often found themselves waiting for
the machines to grind out the results.
It is a part of our
chronicle that these General Motors managers were a keen, inquisitive lot, and
were ever on the alert for anything new. Thus, when it happened on one
occasion that the card readers were producing gibberish, the managers not only
found the cause to be a miswired plug board; they also realized that they had
stumbled onto a means for creating messages in cipher. As a form of comic
relief from the grueling hours to which they were often subjected, they used
some of the waiting time to dig further into this enciphering system. The more
they got into it, the more convinced they became that they had evolved a
cipher system which could not be broken.
During the relaxation of a
luncheon, they told me of this unbreakable cipher system, and I laughed at
them. As it happened, I was no slouch in such matters, since my work in the
Signal Corps Reserve was precisely on this subject. Naturally, one thing led
to another, and before the day was done I had rashly accepted their tender of
an enciphered message to break. Break it I did, though it took until three
o'clock in the morning. (Thereafter my sleep was short but blissful.)
They were stunned by the
news that the unbreakable had been broken, and for the rest of the visit the
agreeable aura of a miracle man followed me about. As a by-product, some
hitherto secret doors were opened up to me. It was one of these doors which
led me, for the first time, to the work of Vilfredo Pareto. The man who opened
that door was Mr. Merle Hale, who presided over the executive salary program
of General Motors.
Hale showed me a research
he had conducted by comparing the executive salary pattern prevailing in
General Motors with one of the mathematical models which Pareto had once
constructed. The fit was surprisingly close. I registered the incident in my
memory along with the fact that Pareto had made extensive studies of the
unequal distribution of wealth, and had in addition formulated mathematical
models to quantify this maldistribution.
In December 1941, the month
in which the United States entered World War II, I took a "temporary"
assignment as a federal government administrator. The original six weeks
stretched into four years and as a by-product gave me an insight into the
problems of managing the federal government. Of course, the principle of the
vital few and trivial many had wide application. At the end of the war (1945)
I embarked on a career dedicated to the field of management: research, writing,
teaching, consulting, etc. By the late 1940s, as a result of my courses at New
York University and my seminars at American Management Association, I had
recognized the principle of the "vital few and trivial many" as a
true "universal," applicable not only in numerous managerial
functions but in the physical and biological worlds generally. Other
investigators may well have been aware of this universal principle, but to my
knowledge no one had ever before reduced it to writing.
It was during the late
1940s, when I was preparing the manuscript for Quality
Control Handbook, First Edition, that I was faced squarely with the need
for giving a short name to the universal. In the resulting write-up2
under the heading "Maldistribution of Quality Losses," I listed
numerous instances of such maldistribution as a basis for generalization. I
also noted that Pareto had found wealth to be maldistributed. In addition, I
showed examples of the now familiar cumulative curves, one for maldistribution
of wealth and the other for maldistribution of quality losses. The caption
under these curves reads "Pareto's principle of unequal distribution
applied to distribution of wealth and to distribution of quality losses."
Although the accompanying text makes clear that Pareto's contributions
specialized in the study of wealth, the caption implies that he had
generalized the principle of unequal distribution into a universal. This
implication is erroneous. The Pareto
principle as a universal was not original with Pareto.
Where then did the
universal originate? To my knowledge, the first exposition was by myself. Had
I been structured along different lines, assuredly I would have called it the
Juran principle. However, I was not structured that way. Yet I did need a
shorthand designation, and I had no qualms about Pareto's name. Hence the
Pareto principle.
T
he matter might well have
rested there had there been a less than enthusiastic response to the
universal. Instead, the new universal became the subject of wide use and
reference. I contributed to this dissemination by coining and popularizing the
term "vital few and trivial many" in the widely read "universals"
paper,3 and in the moving picture film I prepared for American Management
Association on the "breakthrough" process. The resulting wide usage
also brought me some challenges (from Dorian Shainin and others) as to the
attribution to Pareto. These challenges forced me to do what I should have
done in the first place – to inform myself on just what was it that Pareto
had done. It was this examination which made clear to me what I had seen only
dimly – that Pareto's work had been in the economic sphere and that his
models were not intended to be applied to other fields. To make matters worse,
the cumulative curves used in Quality
Control Handbook, First Edition, should have been properly identified with
Lorenz.4
To summarize, and to set
the record straight:
1.
Numerous men, over the centuries, have observed the existence of the
phenomenon of vital few and trivial many as it applied to their local sphere
of activity.
2.
Pareto observed this phenomenon as applied to distribution of wealth,
and advanced the theory of a logarithmic law of income distribution to fit the
phenomenon.
3.
Lorenz developed a form of cumulative curve to depict the distribution
of wealth graphically.
4.
Juran was (seemingly) the first to identify the phenomenon of the vital
few and trivial many as a "universal," applicable to many fields.
5.
Juran applied the name "The Pareto Principe" to this
universal. Juran also coined the phrase "vital few and trivial many"
and applied the Lorenz curves to depict this Universal in graphic form.” 5
References
1 Juran, J.M., "Pareto. Lorenz,
Cournot Bernoulli, Juran and Others," Industrial
Quality Control, October 1950, p. 25.
2
Juran, J.M., Editor, Quality
Control Handbook, First Edition, McGraw-Hill Book Company, New York, 1951,
pp. 37 to 41.
3
The first published use of this term was likely in my paper, Universals
in Management Planning and Controlling." The
Management Review, November 1954.
4
Lorenz, M.O., Methods of Measuring the Concentration of Wealth, American Statistical Association Publication, Vol. 9 (1904-1905),
pp. 200-219.
5
See also, Juran, J.M., Editor, Quality Control
Handbook Third Edition McGraw-Hill Book Company, 1974, pp. 2-16 to 2-19.
(Dr. J. M. JURAN,
Dean of American consultants on quality control, was a pioneer in the
development of principles and methods for managing quality control programs.
He is a veteran of over four decades of international experience in management
at all levels. His clients have included industrial giants as well as small
companies and government departments. He has conducted several hundred courses
in all pans of the world, not only on QC management but on other managerial
subjects as well. Dr. Juran is the author of ten books including 'Quality
Planning and Analysis', (with F. M. Gryna), 'Managerial Breakthrough' and 'The
Quality Control Handbook', which has been translated wholly or partly into
several languages and which has become the international standard reference
work in the field of QR. (1973))
