I always found Bill ready to help, positive and available…. His passion for learning and helping others continued until the last day of his life.
I met Professor William W Cooper for the first time at the IFORS conference in Vancouver, Canada, in the year 1996. For me it was the first major DEA session that I had ever attended. I was also very happy to meet Bill and many other well-known DEA scholars in that conference. I remember Bill was in my presentation and following that we had some discussion in which he gave me a lot of energy to continue on this subject.
Later, in 1997, I met him at Warwick when I also demonstrated the DEAzone website to him.  A couple of years later, Bill wrote me a letter signed and cc to E. Rhodes encouraging me to continue the website.
“The efforts embodied in this Homepage have been important in contributing to the widespread (and increasing) uses of DEA …”.  Signed Bill, 2001

When I dedicate the DEAzone to the DEA inventors, he again wrote me
“I am deeply honored, as I know would have been the case for the late Dr. Charnes, as I am sure will be the case for Eduardo Rhodes. ….

All of us are familiar with this page which we, as well as others, have used to help us in developing and extending DEA for additional uses….

Many thanks. We all owe you a debt of gratitude for these signal efforts”.  Signed Bill, 2001
I always found Bill ready to help, positive and available.  Although I never wrote a join paper with him, in my review paper (published in Journal of Socio-Economics Planning Science, 42(3)) he encouraged me to join Barnett R. Parker and Gabriel Tavares, he mentored the project until it is been published. Later in 2010, I have developed a step-by-step guide for DEA users “The COOPER Framework” (a join paper with Kristof De Witte, EJOR 207 (2010)). The paper published in EJOR, 20102, before submitting this paper Bill read and commented on each and every step of the proposed framework, it was also my honor that he agreed to use such a title “COOPER” for this paper.
His passion for learning and helping others continued until the last day of his life.

Ali Emrouznejad
July 2012
He was passionate about management science research that was informed by and in return informed management practice.
My memories of Bill begin with my first semester at Carnegie Tech as a first year PhD student. I recall an encounter in the “coffee and cookies” lobby with Bill who expounded the GSIA PhD training philosophy that did not require students to take courses as long as they could pass the PhD qualifying examinations. But he did recommend that I take Managerial Accounting course that he requested to teach in the Fall semester. My recollection is that the invitation was more like a command to take his section. Well, I did enroll in Bill’s section. It turned out that Bill volunteered to teach Managerial Accounting because he wanted to show case Yuji Ijiri’s dissertation that Bill was convinced was destined to revolutionize accounting. By the 3rd class session I was totally discouraged. I could not follow the lectures, and any relationships between the lectures, linear programming formulations that bill scribbled on the board and the assigned traditional accounting text seemed totally accidental. I was convinced that I would fail the course and my PhD studies at GSIA would be cut short. My wife however suggested that switch to Neil Churchill’s section. Which I did, and 3 years later graduated from GSIA. However, I recall being petrified of having anything to do with Bill and I deliberately avoided possible encounters with him. For some reason, however, Bill apparently thought very highly of me and when he became the founding Dean of SUPA invited me several times to visit Carnegie Tech and stay with him and Ruthie at their home. Thus began a lifelong mutual relationship. Bill and Ruth came to Israel for XX TIMS International Meeting, June 1973, Tel Aviv Israel, for which I was the Program Chair. My wife Anita and I served as tour guides for Bill and Ruth and for Dick and Margaret Cyert. Bill and Ruth simply fell in love with Israel and always recounted their time in Israel whenever we got together. In 1979 I was the general chairman for XXIV TIMS International Meeting in Hawaii. At the conference I invited Bill and Abe Charnes to present one of the three plenary lectures. The lecture was an early draft of the 1981 seminal DEA paper that I accepted as Departmental Editor for publication in Management Science. We all know how important this paper was for the subsequent evolution of the DEA methodology but from watching the body language of the audience of over 400 people I got that sinking feeling that the import of the DEA concept went by the wayside. For me Bill was a role model. He had an unshakeable and deep commitment to scholarship, academic freedom of inquiry and high ethics. He was passionate about management science research that was informed by and in return informed management practice. In reflecting on my own academic career and scholarship I realize that Bill’s ideals have served to shape and guide my own interdisciplinary path and service to the community of Management Science broadly defined. Arie Lewin, USA August 2012
Most individuals would consider helping found one major educational institution a lifetime achievement. Bill Cooper did it twice and felt in both cases, it was just something he had to do, not something he achieved.
Bill Cooper – Friend and Mentor I had known Bill Cooper for almost 40 years, first as a dean and professor at CMU, later as a colleague and friend. Without question, he had the most significant impact on not only my approach to research, but also my way of dealing with people in general. He had a zest for life. Every day he viewed as an opportunity for a new challenge and the acquisition of new knowledge. The intensity of his love of doing even in his later years eclipsed that of most individuals half his age. Bill Cooper was scrupulously fair in the manner he conducted his research and in his collaboration with others. Always loyal to those he considered friends; he never wavered in his support of friends, even when others faltered. For me, he saw potential where even I saw nothing but problems. It was his faith in my abilities more than my own faith which got me through the challenges of graduate school and beyond. There is a joke which several people use to make about being one of Cooper’s students. The premiums were very high, but they say you have to remember it is a lifetime insurance policy. Regardless of how far or how successful you thought you have gone, Bill Cooper always felt an obligation to see if you could go a bit further. If you had made chair of your department and had a named chair, then he might worry about awards in your future. Even when I made Vice Chancellor at Indiana University, Bill worried that I was losing my research soul and corresponded regularly with me about possible new areas of research interest. Everyone recognized his considerable quantitative gifts and ability to work hard, hard, hard. Frankly while admiring his technical skills and work ethic, I do not think those made him great. Those traits alone would make him good, maybe very good. What made him great? Bill Cooper possessed an extraordinary and rare ability to bring together apparently unrelated issues and problems and synthesize them into something wholly new and wonderful. If you look at the mathematics of his great achievements such as goal programming or data envelopment analysis, the mathematics is not that esoteric. What was special and extraordinary was his ability to see lines of connectivity and paths of solutions where others saw nothing. Nothing. This precious gift very few individuals in any field had to the degree that Bill Cooper did. This gift of Bill Cooper extended beyond his research. In a time when all “business schools”” tended to look the same and produce the same type of graduate, Bill Cooper and a small group of like-minded souls at the then Carnegie Institute of Technology, founded the Graduate School of Industrial Administration, GSIA, now the Tepper School of Business. They created not another “business school” but rather a place for rigorous quantitative analysis of management problems. They helped foster a wholly different approach to problem solving in economics and business management. He saw connection and approaches where others saw nothing. Not content to rest on his administration creativity, about twenty years after helping found the Tepper School, Bill Cooper then turned his attention to doing the same thing for public sector education. SUPA, Carnegie Mellon’s School of Urban and Public Affairs, now the Heinz School, like the Tepper School represented a radical departure from the standard “public administration” education model. He and Toby Davis helped form in the late 1960’s and early 1970’s an approach to public sector problem solving which asked different questions and provided very different insights than others before them. Most individuals would consider helping found one major educational institution a lifetime achievement. Bill Cooper did it twice and felt in both cases, it was just something he had to do, not something he achieved. An extraordinary individual whose like may never be encountered again within our professions. He brought to his research, his vision of learning, and his conduct of living a joy of exploration and an enormous appetite for going beyond what others knew. I am grateful for having had him in my life and hope in some small way; I have conducted myself in a manner which would make him proud. Edwardo L. Rhodes, USA July 2012
This is the passing of an era. Bill was a truly remarkable person. His intellect and his energy are rarely surpassed. His ability to embrace all was exemplary. We are the poorer for his passing.
Bill stands as a giant among us, distinguished for his intellect, his energy and his humanity. Most of us have come to know him from his seminal Work in Data Envelopment Analysis (DEA). However, Bill had a long and illustrious academic career well before he turned his hand to DEA. Indeed, he would have been well into his 60s before the seminal paper on DEA in the European Journal of Operational Research in 1978. Many academics at that age are looking into retirement, but that could not have been further from Bill’s mind at that time. As recently as 2008 when I was still one of the Editors of the Journal of Productivity Analysis he was urging me to get his paper reviewed and a decision made quickly because as he put it ‘I am into my 90s and I do not have long to go’! One can scarcely take in the magnitude of the revolution Bill and his co-authors (Charnes and Rhodes) unleashed with their seminal paper on DEA. The Scopus database reveals that their 1978 paper on DEA has till now (2012) close on 5000 citations. This is 5 times more than the next most cited paper (Saaty’s AHP). There are over 5000 publications in DEA covering theory and applications in areas spanning the entire alphabet from Agriculture to Zones of gas distribution. Bill stood in the 40 years since the seminal paper on DEA as the longest serving father of DEA with a steady stream of contributions throughout that period. Bill was a passionate proponent of the virtuous circle of practice-relevant research where applications benefit from research findings while at the same time they point to new research avenues to be explored. DEA lends itself particularly well to this type of research. I first met Bill at a conference on DEA in 1989 in Austin Texas. We continued to keep in touch since that time. I have benefited tremendously from his research. He often sent me his papers which might have just appeared or were even at a working paper stage. Away from his research Bill was an extremely friendly person. He always had time for people despite being extremely busy. He was supportive of researchers, co-authoring papers with those taking their first steps in DEA and offering friendly advice whenever asked. He was a remarkably kind and considerate person. We are lucky to have known Bill. The DEA community will undoubtedly be the poorer for his passing. However, we can be grateful that he enjoyed a very long and creative life. In my memory at least he will live as long as I live.RIP Bill. Emmanuel Thanassoulis, UK August 2012
William W. Cooper was a real gentleman, with a bright mind and a special skill for explaining his appealing ideas. One of the outstanding features of his charming character was his enthusiasm. Keenness for life and keenness for research.
William W. Cooper was a real gentleman, with a bright mind and a special skill for explaining his appealing ideas. One of the outstanding features of his charming character was his enthusiasm. Keenness for life and keenness for research. The intellectual couple integrated by Bill and Ab Charnes has been one of the most intriguing examples of joint research performance in the history of Mathematical Programming and Management Science. I first met Bill in 1981 in Austin, Texas. It was during an international meeting on Semi-infinite Programming. I met Bill for the second time in Aachen, during the 1991 EURO meeting. He was among the American people who came over to Europe to disseminate Data Envelopment Analysis (DEA). Knox Lovell was also there. I talk to both of them about common future DEA research and invited them to visit me in Spain. In 1994 Cooper was the keynote speaker in the meeting of the Spanish Statistical and Operations Research Society. I presented him my work about translation invariance DEA models as well as my critics about the MIP and MEP measure. As a consequence, we started talking about developing new efficiency measures based on the additive model. At that time, it was for me very stimulating to receive most of his DEA working papers. In 1995 my former University of Alicante distinguished him with a PhD Honoris Causa, and I was his protector. It was my opportunity for knowing him more deeply and for understanding what he was proud about. Basically he was proud of his contribution to the well-being of related people. He was also proud of his wife Ruth and of his common work with Abraham Charnes. Specifically, he mentioned several times the method of “creating theory based on applications”. In late forties and working with the engineer Bob Mellon, they developed the first mathematical programming model applied to industry. It was a completely new blending model of gasolines for used in an integrated oil company. The corresponding paper, under the title Blending Aviation Gasolines, was published in 1952 in Econometrica. Curiously enough, they started trying to solve this problem the other way round, i.e., “applying theory to solve applications”. They resorted to the “activity analysis” due to T.C. Koopmans, awarded later as Nobel Prize in Economy, but they failed. As a consequence of their success they were invited to participate in other applied proyects. One of them is worth mentioning. It was the proposal of G.H. Simonds, the director of the research team of the EXXON refinery in Elizabeth, New Jersey. As a result a new approach was developed by replacing the stochastic coefficients in a linear programming model by random variables. In this way the data with variability out of control of the project direction could be modeled. The results were published as a 1958 paper in Management Science, coauthored by Charnes, Cooper and Simonds, under the title “Cost Horizons and Certainty Equivalents: An Approach to Stochastic Programming of Heating Oil”. Today we know this new approach as “chance constrained programming”, a technique that has been used by many researchers within the stochastic programming literature. Another relevant example of the “creation of theory based on applications” is goal programming, a research branch also created by Charnes and Cooper. For an interesting revision with several examples see their 1977 European Journal of Operational Research article entitled “Goal Programming and Multiple Objective Optimizations. I have been working with Cooper and within a DEA framework since we met for the second time, in issues related to the additive model. Our first and largest paper was written jointly with Park and is devoted to introducing a new additive based efficiency measure baptized as RAM. It was published in 1999 in JPA, one year later than an application of RAM to the evaluation of water supply services in the Japanese region of Kanto. This second paper was joint work with Aida and Sueyoshi and was published in 1998 in OMEGA. Our sixth and last common paper was coauthored with Aparicio and Borrás, devoted to decomposing profit efficiency and published in EJOR in 2011. I would like to close this writing with a basic thought of Bill Cooper. “Probably both DEA and goal programming need to be enlarged to develop new models so as to evaluate quality of life. This issue will require resorting both to “creating theory based on applications” and to “applying theory to solve applications” so that both approaches appear as complementary instead of antagonistic.” Jesus T. Pastor, Spain August 2012
Bill received numerous other awards for his research and academic leadership, including the esteemed John Von Neumann Theory Prize in 1982, together with Charnes and Richard Duffin.
William W. Cooper was born on July 23, 1914 in Birmingham, Alabama and died on June 20, 2012 in Austin, Texas. He grew up in a rough neighborhood in Chicago. After his father became ill, he had to drop out of high school to support his family, and he worked at a variety of odd jobs, including as a professional boxer. His record: 58 wins, 3 losses, and 2 draws. Eric L. Kohler, an Arthur Andersen & Co. partner who taught accounting at Northwestern University, picked Bill up as a hitch-hiker one day on his way to another of his jobs, as a golf caddie. Kohler soon became his mentor and friend, and he loaned him the money to enter the University of Chicago. While at the university, he met his future wife, Ruth, and became friends with fellow student Herbert A. Simon. In 1938, he received an A.B. degree, majoring in economics, and he then accompanied Kohler to the Tennessee Valley Authority, where Kohler served as Comptroller. Bill assisted him by applying his analytical skills to developing the TVA’s required auditing systems and procedures. In 1940, Bill entered the Ph.D. program in business at Columbia University. After completing the coursework in two years, his research was so advanced for its day that his thesis committee could not judge, and would not approve, his thesis. As Bill later said, he “fought the committee to a draw.” In 1942, Bill again followed Kohler, this time to U.S. Bureau of the Budget to help with the war effort, where he was put in charge of all the government’s accounting-related statistics. After a brief return to the University of Chicago, Bill joined the Carnegie Institute of Technology (today Carnegie Mellon University) in 1946. Together with George Leland (Lee) Bach and Herbert Simon, he was one of the founding fathers of Carnegie Tech’s Graduate School of Industrial Administration (now the Tepper School of Business). They pioneered a scientific, interdisciplinary approach to business education, eventually with Ford Foundation support, that is now the norm in leading business schools, and their effort was a key intellectual driver in the development of CMU. From the outset, Bill espoused the need for problem-driven research. Together with long-term collaborator Abraham Charnes, he developed important new mathematical techniques (for example, goal programming, chance-constrained programming, and data envelopment analysis) in the search of solutions to particular applied problems. Their work created a new field, called management science, and Bill was the founding president of The Institute of Management Sciences (which is now part of the Institute for Operations Research and the Management Sciences). In 1968, he became the first dean of CMU’s School of Urban and Public Affairs (now Heinz College). From 1975 to 1980, he was the Arthur Lowes Dickinson Professor at the Harvard Business School, where he developed and supervised an improved Ph.D. program. In 1980, George Kozmetsky, the dean of the business school at the University of Texas at Austin, hired Bill as the Foster Parker Professor of Management, Finance and Accounting, thus bridging three departments. He became emeritus in 1993. Throughout his career, he advised numerous Ph.D. students, including Andrew Stedry, Andrew Whinston, and Yuji Ijiri at Carnegie Mellon, Rajiv Banker at Harvard, and Ramayya Krishna at UT-Austin. Bill was an immensely prolific researcher, even in the last years of his life. Of his more than 545 scientific publications, 35 were in accounting and auditing. In 1981, he became the founding editor of the Auditing Section’s new journal, Auditing: A Journal of Practice & Theory. In 1988, the Section gave him its distinguished service award. In 1985, he was one of the influential voices behind the founding of Accounting Horizons. In 1986, he served as the AAA’s Distinguished International Visiting Professor in Latin America. He received the AAA’s Outstanding Accounting Educator Award in 1990, and in 1995 he was inducted into the Accounting Hall of Fame. Bill received numerous other awards for his research and academic leadership, including the esteemed John Von Neumann Theory Prize in 1982, together with Charnes and Richard Duffin. Together with Ijiri, in 1979 Bill edited a collection of papers in honor of his mentor: Eric Louis Kohler: Accounting’s Man of Principles. Also together with Ijiri, in 1983 he compiled and edited the sixth edition of Kohler’s Dictionary for Accountants. Bill had a wide expanse of knowledge, and he could talk intelligently on any subject raised in conversation, whether in science, the arts, philosophy, sports, business, or politics. And he always made others feel as if they were on his level. He cared intensely about people and ideas, and he was always in search of ways to improve the human condition. Until the last weeks of his life, Bill would come to the office every day to pursue his research. His wife Ruth, a lawyer and advocate of human rights, died in 2000 after 55 years of marriage. He is survived by his brother Leon and his sister Emilie. In addition, he leaves behind numerous former students and colleagues who came to regard Bill and Ruth Cooper as their godparents. Jonathan C. Glover, Yuji Ijiri, Stephen A. Zeff, USA June 2012 See also http://commons.aaahq.org/posts/f19383ed6c
He was a gentle man as well as a gentleman. He treated everyone with respect and was able to accept all the accolades coming his way without ever getting arrogant or displaying the too often evident self-centred and intolerant attitude many much accomplished people show. And he enjoyed the absolute support and love of everyone he knew.
Unfortunately, I came along to DEA in the early 1990s and did not have the opportunity to be Bill Coopers student – as many of my friends had. However, right from the start we became friends – which was not a difficult thing to do with this always gracious and very accommodating man. So I have had the good fortune to have known him for about (only) 20 years of his 97 but it seems like a lifetime. Our relationship grew quickly when I found out that he was a very strong proponent of any and all efforts to apply DEA to real-world problems as often as possible. What he meant by this was to solve problems for real managers and institutions both in the private and public sectors. He was a firm believer that DEA (and actually many other technologies he pioneered) could provide significant benefits to operating managers and DEA should be a standard tool in the consultants’ tool kit. In short, we were both on the same page and enjoyed the interaction on this subject. Bill sort of adopted me into DEA and was a father figure to me in academia. Obviously, this man was an “outlier” in a number of ways, let me just mention two. First, in the scientific world his accomplishments are truly remarkable – but I leave the history part to others. After all, he was in his sixties when DEA was invented with Abe Charnes and then he supervised a number of Doctoral students starting with Ed Rhodes that resulted in a distinguished group of academics. The foundation was laid down and the former students took DEA and developed a significant branch of Management Science (which many say he was the father of) approaches. The DEA literature now consists of perhaps as many as 7-8,000 papers (nobody knows now how many) a real tribute to the versatility of the science. His intellectual leadership in academia is unquestioned and he had received many awards and distinctions but also should have received the Nobel Prize for all his accomplishments. Second, Bill was a gentle man as well as a gentleman. He treated everyone with respect and was able to accept all the accolades coming his way without ever getting arrogant or displaying the too often evident self-centred and intolerant attitude many much accomplished people show. And he enjoyed the absolute support and love of everyone he knew. He really showed to everybody how friendly and happy he always was. We all were lucky over the past 25 years to have known a man who was pre-eminent in so many ways in his own time. Bill’s influenced us while with us, his legacy continues, and will continue for a long time to come. The story about him offering his own office to a visiting professor (although there were other available rooms) is an example of selflessness not many could cite even with others much less accomplished than Bill. He was always ready to help, he would gladly accept an invitation from a young researcher to co-author a paper, have them visit, correspond, and he was happy to mentor and nurture the individual. He was an icon and loved by everyone. His former students idolized him and would go to any lengths to do whatever Bill asked – but when he did this it was with an apology for disturbing them. There are some very special people put on this earth and Bill Cooper was among the very best of those. In my life, I have known only three such people from very different backgrounds. The first one was a professional soldier whom I met in the early 1980s through a common hobby. The second was a Christian Brother whom I met about the same time. And the third was Bill. All three were selfless, extraordinarily smart, gentle and had a heart of gold. And all are, I am sure, assisting the Almighty with his good works. I miss Bill very much! Joseph C. Paradi, Canada August 2012
No words can express the deep sorrow I felt when I heard of his demise.
I cannot help but say how I miss Bill. I met Bill for the first time in 1986 at Dr. Charnes’ office in Austin. In 1993, Bill visited Aoyama-Gakuin in Tokyo where we agreed to write a textbook on DEA. I began to write the first draft in 1996 and the book was published in late 1999 from Kluwer under co-authorship Cooper-Seiford-Tone. I will talk about something that happened during this publication. We exchanged a memorandum on writing this book. First, we agreed it should be a textbook but not a monograph. At that time we had no Windows and e-mail. So, I wrote the first draft in TEX and sent the DVI file as printed matter to Bill by airmail. It took about a week to reach Austin. Bill carefully read my draft and responded to me by revising it with his handwritten materials. It was a wonderful experience for me that, even if I wrote only a few lines on some subject, he expanded it to several pages! His sentences were long with no periods but with much ornamentation. When I was an undergraduate student, I read Immanuel Kant’s Prolegomena zu einer jeden künftigen Metaphysik, die als Wissenschaft wird auftreten können, in the Reclam book. I wondered how the great philosopher expressed his thoughts through continuous long sentences in a multi-stratified manner. I felt the same surprise in Bill’s writing. I first leant to write such long sentences just like composing a symphony. Bill’s brain had a full of polyphonic structure. Moreover, his handwritten letters were difficult to decipher, as many acquaintances know. He said that when he was a schoolboy he was awarded in penmanship. However, after the invention of the ballpoint pen, he came to write speedily to express his flowing ideas one after another. So, his cacography is caused by the ballpoint pen! No words can express the deep sorrow I felt when I heard of his demise. Kaoru Tone, Japan June 2012
Brings tears to my eyes, but what a great life he had!.
Brings tears to my eyes, but what a great life he had! Lawrence M. Seiford, USA June 2012
William Wager Cooper was a great man as a scientist, professor, researcher and friend. He was always ready to help anyone from students to friends and colleagues.
I first met Professor William W. Cooper during my postdoctoral study in 1985/86 as a Fulbright Scholar with Professor Abraham Charnes in the Center for Cybernetic Studies at the University of Texas at Austin. In 1985 the first paper of Charnes, Cooper, Lewin, Morey and Rousseau on sensitivity and stability analysis in Data Envelopment Analysis (DEA) was published and I began working with Professor Charnes in that area. Professor Charnes and I obtained some new results which I shared with Professor Cooper, since he was one of founders and leading researchers in DEA. It was the beginning of our contacts which continued until recently. I remember our meeting at The 12th Triennial Conference on Operational Research, IFORS’90, June 1990 in Athens, Greece. Professors Charnes and Cooper were keynote speakers on DEA and I presented a joint paper with Professor Charnes entitled ”Sensitivity Analysis of the Proportionate Change of Inputs (or Outputs) in Data Envelopment Analysis”. In July of 1991 we met at The 11th European Congress on Operational Research EURO XI – in Aachen, Germany. I also met Professor Cooper at The 14th IFORS Conference in Vancouver, Canada – in July 1996. It was also an opportunity for me to meet Professor Cooper’s wonderful wife, Ruth. After a discussion with Professor Cooper at the Conference I sent him a draft of my paper on sensitivity analysis of the Additive model for the case of change of all data. I incorporated his constructive comments into my paper „Sensitivity in data envelopment analysis for arbitrary perturbations of data“, which was published in 1997 in Glasnik Matematicki. Professor Richard E. Wendell from The University of Pittsburgh and I worked in 1996 on a generalized additive, categorical model in DEA. Professor Wendell, as a very good friend of Professor Cooper, sent him our preliminary results asking for his opinion. Professor Cooper’s response was a ten-pages letter written by hand. In our paper published in 2000 is written: „The authors are indebted to Professor Cooper for his many insightful comments and suggestions.“ In July, 1997 Professor Cooper and I attended the EURO XV – INFORMS XXXIV Joint International Meeting – in Barcelona, Spain. Professor Cooper presented a very interesting paper „Scalar Measures of Inefficiency in DEA“. After my presentation of the paper ”Sensitivity in Data Envelopment Analysis for Arbitrary Perturbations of Data” we discussed the papers. At the Sixth European Workshop on Efficiency and Productivity Analysis, at Copenhagen, Denmark in October 1999, I was together with my former master student and Ph. D. student Valter Boljuncic, who is Professor at the University of Pula and a member of Croatian Parliament. Professor Boljuncic presented our joint paper ”Evaluation of Robustness of Decision Making Units Using Dual Multipliers”. At the Workshop’s banquet we were seated at the table with Professor Cooper and Professor Rajiv Banker and had a very nice long chat during dinner. Here I learned many interesting facts about Professor Cooper’s life including his professional boxing career and the situation with his doctorate. During his stay as a Fulbright Scholar at SUNY, Stony Brook, Professor Boljuncic visited Professor Cooper in the spring of 2001 at the University of Texas at Austin and gave a talk there. In February 2010 I sent Professor Cooper a joint paper with M. Asgharian and M. Khodabakshi on Congestion in Stochastic DEA asking for his opinion of it. His answer in April 2010 was: „Dear Luka: Thank you for giving me an opportunity to read your very interesting paper on Congestion in Stochastic Data Envelopment Analysis. Please also excuse this delayed response by my having been ill and out of the office for some time.“ After comments on the paper he wrote: „I hope you find these comments to be of some interest and many thanks for giving me the opportunity of renewing our contacts. Bill“. I used to send Christmas and New Year greetings to Professor Cooper. He always answered, like in 2008: „Dear Luka: Thanks for your good wishes. It was nice to hear from you, I hope this finds you well, happy and thriving. Best regards, Bill.“ William Wager Cooper was a great man as a scientist, professor, researcher and friend. He was always ready to help anyone from students to friends and colleagues. His ideas had a tremendous influence on the new areas of Management Science, Operations Research and Economics. Among a number of his fundamental contributions, he was a founder of Data Envelopment Analysis together with Abe Charnes and Eduardo Rhodes in their seminal paper published in 1978. I am very fortunate to have had the honor and pleasure to be among those who knew him. I am most grateful for his many kind and constructive comments on my research, and I will always cherish his memory!
Luka Neralic, Croatia August 2012
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To show our appreciation of his work and efforts to be inclusive of other views, we dedicated our book Intertemporal Production Frontiers: With Dynamic DEA to him. We will miss him.
In Memory of W.W. Cooper We first met Professor W.W. Cooper in beautiful Newark, New Jersey, probably in the early 1980s. We were attending a cross-disciplinary conference on ‘Cur- rent Issues in Productivity’ organized by Ali Dogramaci. That was our first formal introduction to DEA. We were interested but also curious about how DEA was related to the earlier work by Professor R.W. Shephard and others working in the area of activity analysis and linear programming. We of course noticed the obvious superficial relationships—distance functions come to mind which were mentioned in the original CCR paper. But we knew there had to be a deeper connection between the CCR School and the Shephard School. This took us quite some time; in 2002 we published ‘Two Perspectives on DEA: Unveiling the Link between CCR and Shephard,’ which appeared in Journal of Productivity Analysis. There we showed that by appropriately normalizing Shephard’s (dual) output price model, the two schools coincide. Over the several decades since we first met ‘W.W.’ as we referred to him, we have had many exciting and fruitful discussions, although we didn’t always agree with his approach. Some of these issues included non-Archimedeans, slacks, congestion, disposability and treatment of undesirable outputs. Rather than rejecting each others papers, W.W. introduced the idea of ‘publishing the referee reports’, allowing the reader to see the various views of these issues side by side. This is a reflection of his academic curiosity and open-mindedness. To show our appreciation of his work and efforts to be inclusive of other views, we dedicated our book Intertemporal Production Frontiers: with dynamic DEA to him. We will miss him. Rolf Fare & Shawna Grosskopf, USA August 2012
In a sense, an entire era ends with Bill Cooper, but he will be remembered for a long time because his intellectual ingenuity will continue to breed new knowledge in those that follow him.
I am deeply saddened to report that Professor William W. Cooper passed away early in the morning on Wednesday, June 20. He was a giant in the fields of operations research, management science and economics and, especially in Data Envelopment Analysis (DEA) that spans all those disciplines. He had a great life making so many important contributions to so many fields, and of course he was the father of DEA. In a sense, an entire era ends with Bill Cooper, but he will be remembered for a long time because his intellectual ingenuity will continue to breed new knowledge in those that follow him. For those of us fortunate to have known him over the years it will leave a huge void in our lives. He was always so generous with his time and so full of new insights. Many have benefited enormously from Bill’s munificence manifested in his personal attention and initiative in not taking no for an answer and sometimes making the impossible possible. Born on July 23, 1914, Bill Cooper grew up in one of the roughest neighborhoods of Chicago. During the tumultuous times of the Great Depression in the 1930s, the responsibility for supporting his family fell on young Bill’s shoulders. He dropped out of high school to earn a living as a prizefighter boxer, losing only three of his 63 professional bouts. His career as a prizefighter, however, instilled in Bill the qualities of persistence and determination that enabled him to accomplish many challenging objectives in his academic life. Continuing on to studies at University of Chicago and Columbia University, Bill learned to settle arguments with incisive arguments rather than with his fists, and he was equally effective. Throughout his career, Bill Cooper espoused the need for problem-driven research. He recognized the need for management researchers to be closely connected with the problems faced by managers in contemporary organizations. To Bill, this did not imply simply applying existing models to solve problems that fit those models. Rather, the objective is to identify new and challenging problems that require original solutions, motivating new basic research and the development of new models to address these problems observed in the field. Such research not only results in improvements in existing management practice but it also substantially enriches intellectual inquiry with the introduction of new problems, models and solution methods to the research literature. This is a tradition that has guided us in DEA research ever since its inception and led to its development as a rigorous method that is useful for addressing so many management and policy problems. Rajiv D. Banker, USA June 2012
Bill enriched the lives of so many of us in so many different ways.
I first met Bill in 1967 when he and Abe Charnes gave a 10 –day course to PhD students (as I then was) and faculty at Lancaster University. The course was held at an hotel in the English Lake District – a setting that matched the excellence of the course. They performed a brilliant double act and seemed to know everything there was to know about mathematical programming theory and applications including fractional programming, chance constrained programming, oil refinery planning and media scheduling. And of course they did know everything! Bill would be in his early fifties and he seemed oldish to me then, although he didn’t seem to age for the next thirty years. In 1981 I stood down as Chairman of the Business School at Warwick and was entitled to sabbatical leave the following year. I wrote to Bill and received an immediate response from him and then a formal invitation from Roy Harris, the Chairman of the Department of Management at UT Austin, to visit, which I immediately took up once I had located Austin on the map. My family and I moved to Austin in January 1982 and stayed until August. We visited Bill and Ruth at their house in the hills, went to concerts with them, I met Bill frequently for lunch – but we never discussed DEA! At that time my interest lay with strategic planning. We were in regular contact from then and my wife, Dorothy, sent a Christmas card every year and Bill later told us he had kept them all. In the mid-eighties I came across DEA, and Emmanuel Thanassoulis and I began a productive period of research into DEA involving applications and theoretical developments and my friendship with Bill facilitated our entry into the DEAcommunity. From then on we met from time to time at conferences. In 1997 I initiated an invitation to Bill to give the Blackett Memorial Lecture to the UK OR Society. (Blackett was one of the wartime founders of OR). Bill visited at Warwick staying at my home. He had a rewarding interaction (certainly for us) with the Warwick DEA group which at that time consisted of Emmanuel and myself, and several doctoral students including Ali Emrouznejad, Rachel Allen, Laura Read, Claudia Sarrico and Ana Camanho. (Victor Podinvoski had recently joined Warwick but I am not sure if he had been lured into DEA at that time). It was a pleasure and honour to host Bill’s stay in the UK. My final meeting was at the Austin Informs conference in 2010. I contacted Bill to let him know that Dorothy and I would be visiting Austin and he invited us to have dinner with him in his residential home. I usually take a bottle of wine to dinner but didn’t on this occasion which was fortunate as the home was dry. At dinner the waitress took our drinks order and the choice was several fruit juices or milk. We ordered our drinks but Bill did not order. When the drinks came the waitress set up a row of all the options for Bill – five in all. With a twinkle in his eye Bill said ‘I am heavy drinker you see’. He proceeded to take sips from all the drinks during the meal. As many of you know the DEA stream at Austin was in Bill’s honour. He attended every day and many people had a chance to speak to and about Bill at the stream or the lunch held in his honour. When Bill spoke there was a hint that it would be the last time he would meet many of us. Bill enriched the lives of so many of us in so many different ways. Robert Dyson, UK August 2012
One of the many things I learned from him is not to complain about negative referee reports. Papers get rejected but in his view that does not mean the research is meaningless or bad or that you should stop.
Bill Cooper was a man who wore many hats and who had many talents. For brevity’s sake, I will focus on the work for which he is most known, that on efficiency using Data Envelopement Analysis (DEA) which he invented with Charnes and Rhodes in 1978. Also I will only comment on our joint works. Working on the stochastic frontier approach (SFA), developed by Aigner, Lovell and Schmidt (1977), I joined the economics department of the University of Texas at Austin (UT) in 1986. Bill was a professor in the business school at UT. In those days SFA was viewed as the archrival of DEA. Although the Business School was located in the same building, I avoided his office, since I was a student of Dennis Aigner. However, it seemed odd not to read some of the DEA paper, especially when the two main architects had offices in the same building. So sometime at the end of 1986 I went to the Center for Cybernetic Studies for some of Bill and Abe’s working papers. The secretary informed me that I could not get any of those papers without their approval and suggested that I talk to Professor Charnes, whose office was at the Center for Cybernetic Studies. Based on what I had heard about Abe, I did not have the courage to go to his office and ask for his permission. Two years later (in 1988) I met both of them in Chapel Hill at a conference that Knox Lovell organized with Arie Lewin. This was my first ‘real’ conference and I met many of the top people working on DEA and SFA. I remember talking to Bill at the airport because we were waiting for the same flight. The SFA group (Knox Lovell, Peter Schmidt, Robin Sickles and some juniors like Paul Bauer and myself) was also attending the conference. Although there were some disagreements on issues of functional form, distributional assumptions and presence of noise, I was relieved to see that there was no real fight between the DEA and the SFA group. At the end of the conference Knox said: “It was fun …., I did not lose my shirt.” This gave me the impression that he had also been apprehensive regarding the possibility of acrimonious exchanges. The disagreements are still debated today, although the gap has narrowed down in recent years. Although I encountered Bill again at many conferences (mostly on efficiency and productivity) after 1988, my real interaction with him was through some of his PhD students (Bardhan and Kwinn) and a visitor (Xuelin Yu, an engineer from Tianjin, China) who came to UT to work with Bill on DEA. My first academic work with Bill started with the Chinese aggregate time series data that Xuelin had. We examined performance of Textiles, Chemicals and Metallurgical Industries after the reform. The paper “DEA and stochastic frontier analyses of the 1978 Chinese economic reforms” (Cooper, Kumbhakar, Thrall and Yu) was published in Socio-Economic Planning Sciences 29, 1995, pp. 85-112. While working on the paper our conversations were often orthogonal because I was not a proponent of DEA and Bill was not an econometrician. However, he was never an extremist arguing that SFA had no value; his interest was to come up with a method that could bridge the gap between DEA and SFA. We did this in a paper using data on Texas secondary schools. We used DEA first to find the schools that were fully efficient. This information was then used, in the form of a dummy variable, in the OLS regression to test whether the relationships for efficient and inefficient schools were the same. The paper “New Uses of DEA and Statistical Regressions for Efficiency Evaluation and Estimation With An Illustrative Application to Public Secondary Schools in Texas” (Arnold, Bardhan, Cooper and Kumbhakar) was published in Annals of Operations Research 66, 1996, pp. 255-277. We continued working on this idea of joint utilization of the DEA and SFA methods. To make sure that our results were not driven by the Texas school data, we decided to analyze it further via simulation. The results were reported in “A Simulation Study of Joint Uses of Data Envelopment Analysis and Statistical Regressions for Production Function Estimation and Efficiency Evaluation” (Bardhan, Cooper and Kumbhakar), Journal of Productivity Analysis 9, 1998, pp. 249-278. In the first draft Bill added another coauthor who was probably not even aware of his co-authorship and knew nothing about the content of the paper. At the end, his name was dropped. I have never seen any one more generous than Bill, perhaps to a fault, so far as co-authorship is concerned. This issue of generous co-authorship came up again in the last two papers that I worked with him. Both these papers deal with joint advertising vs. service specific advertising in military recruitment. Bill was very fond of this topic. The first of the two papers is: “Alternative Statistical Regression Studies of the Effects of Joint and Service Specific Advertising on Military Recruitment” (Brockett, Cooper, Kumbhakar, Kwinn and McCarthy), Journal of the Operational Research Society (2004). The story behind the first paper goes like this. Bill had a PhD student (Michael Kwinn, a Major at that time in the U.S. military) with whom he and Brockett wrote a DEA paper. Bill asked me to assign Michael (who took my econometrics class) to work on a paper using the military recruitment data that he was using for his dissertation. The idea was to use the same method we used in the Texas school paper. Michael asked a Captain in the army to run the SFA models. Bill happily added the Captain as a coauthor. When military recruitment fell short of targets during the war with Iraq, Bill saw the opportunity of addressing the same issue (as above) using the military recruitment data again. So we wrote another paper with some additional insights on advertising. A marketing expert was added as a coauthor (in addition to the five in the other paper) to add values on the advertisement side. The paper, as far as I recall, was first submitted to Management Science. But MS was taking too long and Bill could not wait. So he wrote to the editor that the issue was too important to wait and withdrew the paper. Finally he submitted it to Socio-Economic Planning Sciences on the condition that the editor would do a quick review. The editor kept his promise. In the final version of the paper another coauthor was added. As a result, we ended up publishing the paper “Estimating Elasticities with Frontier and Other Regressions for Use in Evaluating Different Advertising Strategies for U.S. Army Recruiting” Socio-Economic Planning Sciences 42, 2008, 1-17, with seven coauthors (later on a reviewer joked about the number of authors in private conversation). After moving to Binghamton we lost touch other than through the occasional e-mails. Because of his deteriorating health he stopped attending conferences (so I missed seeing him) but never stopped writing papers. Whenever I e-mailed him asking about his health, he talked about it as little as possible, focusing on his research and not on personal issues. He decided to postpone his knee surgery because that would take his time off from research. His photographic memory helped him to work on several projects at the same time (parallel processing) and switch discussions on age old topics seamlessly. In casual conversations in his office, he would talk about his research with Charnes in the 1950s, before I was born, in such detail as though it was yesterday. He kept his papers (all versions) in several file cabinets. If you asked for a copy, he would know exactly where to look for it, take out the whole file and put it back after the paper was copied. Unlike others, Bill used to carry a bag from the hotel to the conference site with 50 to 100 copies of the paper he would present in a conference. I offered help to carry the bag a couple of times while walking with him but he would not let anyone else carry his bag. He would always wear a tie and a jacket no matter whether he was flying or in his office working, except perhaps on the weekends – although he would still be working in his office even then. Bill never used a computer, at least before 2001 (when I left UT, Austin). Once he told me that his secretary wanted to teach him how to check his e-mails. He refused. In every morning the secretary would printout of all his e-mails, Bill would then handwrite his response on the printed version. Finally, the secretary would type and e-mail them. It worked well in the sense that no e-mail was unanswered – except perhaps some were late because secretarial help was not available during the weekends or holidays (though Bill himself would work 24/7). He handwrote all his papers, no cutting and pasting, filling the whole space in the first line of the pad and then gradually moving to the right in a way that the last line would have only a couple of words, forming a kind of inverted triangle. He would fill up several writing pads in this way for every paper. Once something had been written, he would resist deleting anything. One of the many things I learned from him is not to complain about negative referee reports. Papers get rejected (he talked about his DEA paper rejected in the Quarterly Journal of Economics): but in his view that does not mean the research is meaningless or bad or that you should stop. Although he and Abe had some rough encounters with Evans and Heckman on the Bell merger issue, he never took things personally. To him the essence of this debate was to emphasize on cross-validation of results with alternative theories. He showed us the thick file containing the correspondences with editor of MS in which some of the exchanges/debates were published. Bill was a mentor to me in many respects, and I will miss him dearly. Subal C Kumbhakar, USA August 2012