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'''Walter Andrew SHEWHART'''

b. 18 March 1891 - d. 11 March 1967

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'''Summary.''' Shewhart was the father of statistical methods of 
quality control.
His methods were closely related to an epistemology of physics and
application to economics and industry in his time.

Born in Illinois, Shewhart first pursued his tertiary education at the 
University of Illinois,
and was awarded his PhD in Physics from the University of California in 1917.
He was an Assistant in Physics at the University of Illinois in 1916-17, and 
then became Head of the Physics Department at the Wisconsin Normal School at 
Lacrosse in 1917-18.  In 1918, he was offered a job with the Western Electric 
Company, and was later transferred to the Bell Telephone Laboratories in 1925;  
he remained in their employ until his retirement in 1956.

Shewhart's name is associated with methods of statistical quality control in 
industrial mass production (Shewhart control charts), but his contribution
to the field of statistical techniques must be placed within the background 
of a 
theory of knowledge which he developed in the specific context of industrial 
production.  Shewhart was  profoundly
influenced by the philosophy of pragmatism of C.S. Peirce, W. James and C.I. 
Lewis; 
this he put to work operationally in the field of engineering.  At the same
time, he tried to  conceptualize the collective aspect of work
in an enterprise;  this caused him to be equally well known in the field of 
management,
particularly thanks to W.E. Deming (q.v.) who promoted his views.  Through 
Deming, 
Shewhart became well known in Japan where he consequently played an important 
role in the development of methods of management and quality which are 
associated with the name of K. Ichikawa.

Work on control charts originated in a political decision made by the 
Engineering Department management at Western Electric, which wished to define 
scientifically a method for ensuring  "a Company-wide view" of what 
constituted 
quality assurance.  Under the direction of R.L. Jones and G.D. Edwards,  an 
entire team began to attack these problems:  in addition to Shewhart, one 
should also mention H.F. Dodge, E.C. Molina, T.C. Fry, and H.G. Romig.  When 
the Bell Telephone Laboratories were set up officially in 1925, engineering 
inspection appeared as part of their organizational chart.  In 1931, Shewhart 
published his entire work on control charts, in a masterly treatise which still 
remains relevant today.  The application of these statistical quality assurance
methods is an achievement of which Bell Labs is still proud (Fagen, 1975).

Control chart methods are particularly well suited for use in workshops,
as a result of their  elegant usage of graphical representations, 
which limit the operator's need to resort to calculations.
Since product quality is defined by a set of measurable physical quantities,
which are assumed to follow statistical distributions, the control charts 
provide a relatively simple procedure for the visual representation of the 
evolution of the population  mean and standard  deviation. 
So far as statistical background was concerned, Shewhart first made use of 
Karl Pearson's (q.v.) theory of distributions, 
which he complemented with the small sample theory of "Student" (Gossett, q.v.) 
and Fisher (q.v.).  
He introduced the concept of ``rational subgroup" to define the method and 
frequency of sampling.

Control charts were, however, only the tip of his personal iceberg.  
Although he
worked in industry, Shewhart remained a physicist, interested in problems of
measurement in experimental physics, and in the nature of the acquisition of 
knowledge.  
He believed profoundly in the statistical nature of all physical laws, and
attacked  any deterministic concepts: 
<blockquote>
We ordinarily think of the physical and engineering sciences as being exact.
In a majority of physical measurements this is practically true. ...
With the introduction of the molecular theory and the theory of quanta,
it has been necessary to modify some of our older conceptions.  Thus, more
and more we are led to consider the problem of measuring any physical 
quantity as that of establishing its most probable value.  We are led to 
conceive of the physico-chemical laws as a statistical determinism to which
the "law of large numbers" imparts the appearance of infinite precision.
(Shewhart (1913))
</blockquote>

To provide a theoretical foundation for the use of control charts, Shewhart,
developed the concept of a ``constant
system of chance causes".  Intuitively, the idea is simple:  such a system is
a random sytem governed by a statistical distribution independent of time.
The control chart allows us to detect the occurrence of significant causes 
of perturbation (called assignable causes), which can then be tracked down and 
eliminated.  One can thus progressively (as experience proves, according to 
Shewhart) eliminate all assignable causes, and the system can then be said to 
be ``under statistical control".  

Shewhart's theories create a bridge between the epistemology \footnote {the 
theory of the methods
of grounds of knowledge} of measurement
and the notion of human organization which must make the process of 
measurement work.  Statistical control according to him consists of three 
phases:  
specification, production and inspection, corresponding respectively to making 
a hypothesis, carrying out an experiment and testing the hypothesis.  ``The 
three
steps consitute a dynamic scientific process of acquiring scientific knowledge" 
(Shewhart, 1939, p. 45).  These three steps were reformulated by Deming under 
the name 
``Shewhart cycle", and they arise in recent developments in the theory 
of organizations, such as organizational apprenticeship, of which Shewhart 
appears to have been a forerunner.  In the same book, he writes: ``mass 
production viewed in this way constitutes a continuing and self-corrective 
method for making the most efficient use of raw and fabricated material". 

A paradox remains in the social persona of Shewhart.  His works, full of
references to physics and to very diverse technical areas, make difficult 
reading and his lectures were little 
understood by industrialists.  On the other hand he is the inventor of 
quality control
which has been well accepted by industry, and which is recognized as easy 
to use.  Clearly the weight of AT&amp;T in American industry played an essential 
role in the promotion of his work, from the moment when the firm decided to 
support it.  But one must also stress, his 
great personal ability to form alliances and weave relationships among
institutional teams, which was essential to the  adoption of his ideas.
He played masterfully the game of recognition by agencies, learned societies 
and engineering associations.  Already in 1929, he obtained funds to create a 
Joint Committee of the American Society for Testing Materials and the powerful
American Society of Mechanical Engineers.  This resulted in the publication 
in 1935 of a standard which was later adopted during the Second World War 
for the requirements of the military.  One should also mention the promotional
effects of the lectures which he delivered in London in 1932, at the 
invitation of
Egon Pearson (q.v.).  The British, who did not wish to be left behind in this area,
undertook several studies which later appeared as publications of the Royal 
Statistical Society. 

During his lifetime, Shewhart was the recipient of many distinctions.  Among 
these were his founding membership of the Institute of Mathematical Statistics, 
of which he was elected Fellow in 1937 and President in 1944.  He was a founding
member of the American Society for Quality Control in 1947, and was their first
Shewhart Medallist in 1948.  He was elected to the Presidency of the American
Statistical Association in 1945, and was awarded the Holley Medal of the 
American 
Society of Mechanical Engineers in 1954.  He was a member of the International 
Statistical Institute from 1950, and of the Royal Statistical Society which 
elected 
him to honorary Fellowship in 1954. 

Shewhart was nevertheless a modest and 
magnanimous individual, who believed in the fertility of collective work, and 
the value of 
exchanges 
between disciplines and professions.  He saw the role of the statistician in 
an organization as that of the coordinator of several experts involved in the 
process of the production of knowledge.


====References====
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|valign="top"|{{Ref|1}}||valign="top"|   Deming, W.E.  (1978).  Shewhart, Walter, A.  In ''International Encyclopedia of Statistics''.  Ed. W.H. Kruskal  and J.M.Tanur, Free Press, New York. Vol. 2, 942-944. 
|-
|valign="top"|{{Ref|2}}||valign="top"|   Eisenhardt, C.(1990). Shewhart, Walter Andrew. In ''Dictionary of Scientific Biography'', Vol. 18, Supplement II, 816-819.  Scribner, New York. This contains a detailed bibliography. 
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|valign="top"|{{Ref|3}}||valign="top"|   ''Industrial Quality Control.'' (1967), '''24'''. Special Issue in  Memory of Shewhart, containing several testimonials. 
|-
|valign="top"|{{Ref|4}}||valign="top"|   Fagen, M.D. (Ed.) (1975). ''A History of Enginering and Science  in the Bell System, The Early Years (1875-1925)'', Vol. 1.  Bell Telephone  Laboratories, N.J., Especially:  Chapter 9  ``Quality Assurance". 
|-
|valign="top"|{{Ref|5}}||valign="top"|   Shewhart, W.A. (1931). ''Economic Control of Quality of  Manufactured  Products.'' Van Nostrand, New York and MacMillan, London (501 pages). 
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|valign="top"|{{Ref|6}}||valign="top"|   Shewhart, W.A. (1939). ''Statistical Methods from the Viewpoint  of Quality Control.'' The Graduate School, U.S. Department of Agriculture, Washington D.C.  (105 pages).  Republished by Dover Publications with a new Foreword by  W.E. Deming in 1986.
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Denis Bayart

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