The Craft of Decision Modelling is a seminal contribution to the literature of operations research and mgt science; the treatment of material is unique and the subject is important. For problems in real world operating systems, it introduces readers to the important contextual realities, principles, and craft issues present when models are used to achieve understanding.  It is valuable for students and beginners and for a wide spectrum of experienced analysts, particularly those teaching in educational and training programs. 

The term decision modelling in the title may have different meanings for different readers. Rivett means the work of helping client decision makers improve their understanding of problem situations and doing so by creating intellectual constructs--that is, models--for selected phenomena in them and then employing these models to generate findings that shed useful light. Rivett's decision modelling denotes what others may call the practice of operations research and management science. 

Patrick Rivett is one of the early British post-war pioneers of operations research. After an education in mathematics, he began his OR career at the British Coal Board, and it has included varied consulting and educational appointments, the authorship of numerous papers and six other books, and presentations of his views on analysis to the general public. This book is in many ways a distillation of the lessons he has learned in his long, varied, and successful career. 

Toward the end of the book, after appealing to dictionary definitions of the terms, Rivett offers the key clue to the material he chose to present: "Education is a process of maturing and of producing certain attitudes of mind. Training is a drilling process.... Hence one is trained in linear programming but not educated by it" (p. 291). Against this background, it is clear that this book is about education: understanding how OR/MS works in practice Rivett describes some of the appropriate realities, basic attitudes, principles, and needed craft skills; and he pays no attention to training in the techniques that are the usual dominant fare in OR/MS introductory texts and academic programs.

The introductory chapter (pp. 4-9) sets the tone: 

"... life does not proceed with the stately time table logic of a university course. Issues are not clear cut, data are ambiguous and it is never the case that the information with which one is presented is necessary and sufficient for the task. It is, nowadays, more likely that one is grappling with too much information rather than too little.... To those trained in quantitative disciplines it can be a shock to be thrust into an industry (even a scientific one) or into a service or a government department and find

that most people are not quantitatively oriented: decisions often emerge by stealth and emotion, reason is not the driving force, and much energy is consumed by fighting one's colleagues for resources. The picture of the pure analyst holding the world at bay while he does his sums does not apply. He is not on the bank of the river watching and modelling life as it goes by, but is out of his depth in a frail canoe, shooting the rapids." 

Of the analysts, Rivett says: 

"Their task is to hold up a lantern in the dark.... it is not the job of the analyst to be so much at arm's length from the managers he is serving that he is dissociated from them.... The analyst has to laugh when the managers laugh and weep when they weep. And still be calm and professional."

In the first part, Rivett explains how to cope with this complex life and its relationships by using nine examples chosen from his and his friends' professional careers, each illustrating principles of good practice and each accompanied by a chapter discussing the ideas introduced by the example. The diversity of these ideas is suggested by the chapter titles: 

"Decisions and the scientific method," 

"Logic and common sense," 

"Describing a problem," 

"Uncertainty," 

"Deterministic problems," 

"Forecasting," 

"The analyst," 

"The anatomy of organizations," and 

"Bridge building." 

The second part consists of five chapters: 

"Focal points," 

"The analytical process," 

"Practical matters," 

"The future," and 

"Closing thoughts." 

The hallmark of the book is Rivett's wise and witty observations about the realities of practice; on almost every page, something will cause the experienced

practitioner to vibrate sympathetically. For example, in the chapter on decisions and the scientific method (pp. 19-38), we read:  "... there is no such thing as a neutral value free measure. All measurement involves a view of the world."

Of problems in which optima may be sought: 

"Because of the mathematical seductiveness of such problems, they have achieved more attention from researchers than their incidence in the real world demands."

"There is a tendency to regard uncertainty or variability as reprehensible and something of which to be ashamed. But it is uncertainty, not certainty, which is the nature of the universe." 

"One of the temptations to which all modellers are subject is that where seductively elegant methods are available they may be used carelessly and without regard to the assumptions that have to be made."

"Objectives evolve and emerge during a study." 

"... we operate in a changing environment and during a study the world will change."

"... why have a model? The answer ... is that there is too much information and too much complexity in the problems we tackle. We have

to simplify." 

"An important quality of a model should be its capacity to reach out into the unknown or the unknowable." 

"The more variables you need to describe something the less you know about it." 

"It is particularly important not to impute objectives to others because they make sense to the model builder." 

"Constraints can too easily be accepted as 'given' and must never be accepted with docility." 

"The problem as first given to a research team nearly always has to be changed and the most common reason for the rejection by management of a research team's proposals ... is that the team has 'solved' the wrong problem."

"... basic to all this ... is the overwhelming need for the analyst to visit and observe what is going on and to be personally involved wherever possible." 

"... when data can be made available in profusion at the touch of a button, it is tempting to sit back and carry out pre-packaged analyses. Never, never, never do this. Always go to the source of the data."

"... it must never be forgotten that we are dealing with people. Behind the data sheets and the computer printouts, behind the graphs and tables, behind the mathematics, are people in all their emotions, in all their contrariness and bloody mindedness and in all their humanity. The man or woman can always beat the system."

I am tempted to compile a list of observations for each of the 15 general discussion chapters in the two parts of the book--but I would exceed the space allotted to a review, and I would deprive the reader of the pleasure of discovery. 

There is one temptation I cannot resist: In the penultimate chapter, Rivett discusses the stark contrast between what the usual academic OR/MS programs train a student to do and what he/she will later have to undertake in practice; his parting shot is, "The important point which some universities have not grasped is that education and training are not mutually exclusive." This book can be a major contributor to academic programs that wish to undertake serious education for the practice of OR/MS as a complement to their traditional training in its techniques.

Rivett includes a carefully selected bibliography suggesting further reading and an index (which I wish was more comprehensive, as many readers will want to rediscover quotations, and the present brief index will not help much in such a search).

For some time, OR/MS has needed to develop a maturely realistic epistemology of practice, that is, a coherent view and account of its origins, nature, methods, and limits. This book is the most important contribution to this goal to appear in recent years. OR/MS workers, whether in academia or practice, have much to learn from it--and its keen wit and down-to-earth observation of the realities of practice make it as attractive and easy to read as it is important.

Hugh J. Miser 199 South Road, Farmington, Connecticut 06032-2522

Creativity and Modelling 

THE CRAFT OF DECISION MODELLING, Patrick Rivett, New York: Wiley, 1994, ISBN 0-471- 93962-5, 304 pp. 

Review by Peter Wakker, University of Leiden 

Patrick Rivett was trained as a mathematician, and was one of the main initiators of Operations Research in the UK. He is an experienced consultant and a radio and TV broadcaster. In short, he has all the qualities needed to write a thorough as well as entertaining work on decision making. The present book is meant for teachers and graduate students in decision making, and concentrates on modeling. 

Rivett writes (p. 3): ‘We shall therefore operate in the no man’s land between the managers and executives who are faced with decision-making problems and the specialists in mathematics . . . management science.’ The modeling part of decision-making is the most important part, but it is difficult to pin down tangible knowledge. Thus the book contains entertaining descriptions of experiences and lessons from modeling in practical cases, but it will not be easy to describe or test knowledge of students who have read the book. 

When the author points out that examples (‘Lives’) at the end of a chapter need not relate to the preceding material, it does not seem to distress him (p. 5): ‘It is hoped that this approach will illustrate that rich weaving of theory, concepts, ideas, and problem formulation which form the fabric of professional life and that in so doing we shall show not only what is the attitude of mind of those who do this sort of thing but also why it is what it is.’   

The examples are all entertaining and demonstrate creativity rather than routine. As a consequence, there is no simple way to describe ‘the message’ of the book. Let me only give two of the many entertaining examples. 

One concerns the optimal sizes of parishes (p. 121). A bishop of the Church of England requested the OR group in his local university to investigate the optimal size of parishes. It was conjectured that the probability of church attendance would be determined by the inverse of the square of the distance. The team was surprised to discover, however, that most worshippers did not attend their nearest church. It was concluded that not distances should be optimized but instead the variety of styles of churchmanship. A routine approach by distance-optimizing techniques would not have given a good solution to the problem, but understanding and creativity did. 

The second example is from the UK mining industry (p. 170). When at a certain time it became difficult to sell small-sized coal, much effort was put into producing more large-size coal. However, the problem was not one of product mix but of total sale: the decrease of sales of small-size coals was only a first symptom of a general decrease of coals sales, which had not been foreseen by forecasters. As usual, after describing the example, the author gives a moral of the story. Here the moral is that people tend to see in a situation what they want to see and tend to tell others what they want to hear. 

I made several notes of nice citations gathered in the book, such as 

“If you’re so smart, how come you ain’t rich?” 

"The more variables you need to describe something the less you know about it." 

“No man can ever step twice into the same river.” 

The spirit of the book can be best described by the author’s words from the preface: ‘Model building . . . is fun’.

Professor Patrick Rivett, Pioneer in OR

Monday 29 April 2013 06:01

Operational research - the use of scientific methods to solve organisational problems - came to the fore during the Second World War under the influence of distinguished scientists like Patrick Blackett, Charles Ellis and Charles Goodeve. The unique contribution of Patrick Rivett was to provide the focus and drive necessary to transform a military activity into one widely used in UK industry and Govt. 

[Berwyn Hugh Patrick Rivett was born on 2 April 1923 at Oswestry, but the family moved to London when he was only 3 months old. An elder brother had obtained a place at King's College and it was felt that he should live at home.]

Although he was born in Shropshire, Pat Rivett's family moved to London when he was three months old, because an older brother had obtained a place at King's College. Their father was an inspector with the NSPCC, covering the Old Kent Road. Pat Rivett himself was a dedicated Christian and politically left of the centre until his mid-forties.

In due course, he followed in his brother's footsteps, with the intention of becoming a schoolteacher, but a first class degree in Mathematics resulted in his being drafted in 1943 into a statistics group within the Ministry of Supply. Rivett was assigned to a team working on the quality control of ammunitions production, and the transformation of the mathematician to a practitioner interested in real problems was quickly made. His natural talent for communication was first put to the test when explaining control charts to operatives who had left school at 14.

The ending of the war changed the nature of the work and Rivett was transferred internally to the Ordnance Board, working directly to military officers on fragmentation patterns of shells and bombs. He could not see the point of it, but kept himself very busy by first obtaining an MSc at Birkbeck College and then lecturing two nights each week at Battersea Polytechnic. The extra money that he earned enabled him to marry, as it so happened into a South Wales mining family, and that produced a strong emotional desire to work in the coal industry.

In 1951, he became head of the National Coal Board's Field Investigation Group, which he built up to what became the largest operational research group in the UK. High recruitment standards were set and staff then taught each other about new developments through a formalised learning process. The excellence of the work carried out became widely known, and Rivett was delighted when his staff went off to other jobs, so spreading operational research (OR), with many subsequently obtaining professorships.

During this period, he became the honorary secretary of the Operational Research Society when it was first formed from the OR Club. Working from his desk in the Coal Board, Rivett set about transforming the club into a learned society, with a quarterly publication which has since become a leading international monthly journal.

Whilst at the Coal Board, he had visited the United States and even taken a two-week course at the Case Institute of Technology, where he had struck up a close friendship with Russ Ackoff. When Lancaster University was founded, its first Vice-Chancellor decided that Operational Research would be one of the first two departments to be formed and Ackoff recommended Rivett to Charles Carter. Thus in 1963 he became the first professor of OR outside the US.

Once again, he was in at the beginning of something new and set about the work with enormous enthusiasm. The foundations were laid for the highest regarded OR department in a UK university. Close relationships were established with industry. Both teaching and research had a strong applications flavour. Other universities quickly noted its success and Rivett was approached by Sussex, which at that time had a glamorous image. Making what he later described as a great mistake, in 1967 he moved to Brighton. He was thoroughly miserable. The university did not like his contacts with industry, there were demonstrations against what he was trying to do and his filing cabinets were broken into. When his wife died and he was left with a young daughter, he worked part-time, before retiring in 1988 when the opportunity presented itself. Shortly after retirement, he found great happiness in his second marriage. A move to Cumbria enabled him to renew his contacts with operational research at Lancaster. With more time for research, he worked with health authorities in Lancashire on the delivery of health care for the frail elderly and the preventive management of coronary heart disease, because he firmly believed that OR was to improve the human condition.

He also replied to the 50 or so letters that he received each week, for his natural affability had made many friends. Indeed his eloquence could make any topic sound exciting, not least when he was talking about football, in which Pat Rivett had a passionate interest, and he sentimentally supported Millwall to the end.

Alan Mercer

Patrick Rivett  (April 2, 1923 – July 3, 2005)

Brief Biography

B. H. P. (Pat) Rivett was a pioneer in operations research in the United Kingdom in both industry and academia.  He was an early and leading expositor of OR and served as president of the Operational Research Society, the "professional home of operational research researchers and analysts in the UK."   

He was born in Shropshire, England and moved to London with his family shortly thereafter.  He graduated in Mathematics (First class) from Kings College, London in 1943, and was drafted into a statistics research group within the Ministry of Supply.  After the war, he stayed on at the Ministry, rising to become a senior scientific officer.  Although he had no prior involvement with OR beyond statistics, in 1951 he became head of a Field Investigation Group (FIG) that was carrying out OR in the coal mining industry, which had been nationalized as the National Coal Board (NCB). 

Under Rivett's guidance, the FIG staff quickly grew to 60 and eventually became the largest OR group in the UK.  Maurice Kirby [Kirby 2003] believes that this was due in part to " Rivett's infectious enthusiasm for operational research which was complemented powerfully by his considerable skills in exposition" as well as by some "startling results" from early projects.  One such early FIG project analyzed a 1950 mining disaster in which 80 miners were killed by fire and fumes. The project determined that the high death toll was due in part to poor communications that slowed evacuation.  The team recommended moving three telephones and installing three more, which an early hand-calculated simulation using tables of random numbers determined would have halved the evacuation time. 

Rivett promoted a practical, hands-on approach to OR, and personally went down more than one hundred mines, operating on the same hours as the mine workers.  During two months touring the U.S. and a two-week training course taught by Russell Ackoff at Case Institute of Technology he learned about some more mathematical aspects of OR.  After a subsequent 3-4 months at Case he returned to the UK and organized Saturday morning study groups at the FIG. 

In 1960 he joined Arthur Andersen & Co. and established the company's U. K. office, where he was exposed to a wide variety of industries. However he was not keen on being a consultant, judged on his chargeable time rather than the quality of his work.   In 1963 he and three others who had worked for NCB established an OR group at Lancaster University, the last of seven new British Universities inaugurated in the 1960's.

At Lancaster, Rivett was the first established chair in OR at a British University and laid the foundation for what soon became a highly regarded department.  It was the first at Lancaster to establish a Masters Degree program in OR and to hold a short course on simulation for people from industry, commerce, and the public services.  The Masters program was modeled on Ackoff's approach at Case, with industrial practice by postgraduate students being of paramount importance. 

In 1967 Rivett left Lancaster to become Professor Operational Research at the University of Sussex, where his contacts with industry caused difficulties with the University and some students.  He retired from Sussex in 1988, and became an honorary professor at Lancaster.  In retirement he was involved in consultancy work with the National Health Service in Lancashire on delivery of health care for the frail elderly and the preventive management of coronary heart disease.  He visited the University of Mississippi twice, once for a full year and later for a semester.   

The Operational Research Society (ORS) was formed from the more informal OR Club in the UK in 1953 with Rivett as the first honorary secretary, serving in that capacity for about eight years.  He served a two year term as president.  In 1955 Ackoff proposed an international OR conference, which was held at Oxford in 1957, sponsored by the ORS, the Operations Research Society of America (ORSA) and The Institute of the Management Sciences (TIMS).  Together with Sir Charles Goodeve, Rivett represented the U.K in setting up the conference.  This conference led to the creation of the International Federation of Operational Research Societies (IFORS), an umbrella organization of what grew to be 50 national societies.  IFORS was controlled by a Board of Representatives with one member per society, with Rivett representing ORS.  He was later instrumental in the launching of the Operations Research Society of South Africa.  

Through his textbooks, addresses, television programs, and publications in non-OR/MS Journals, Rivett was a leading evangelist of OR.  He extolled the OR method with an emphasis on applications.  His scholarly works included a series of papers on multivariate scaling.