The making of ‘EORMS 3e’

‘Encyclopedia of Operations Research and Management Science’ (third edition) was Saul Gass’ last project.

“Dedication: To the memory of my very dear colleague Saul Irving Gass, an O.R. pioneer, practitioner and statesman, and a true scholar and friend. Saul passed away on March 17, 2013, as this edition of the ‘Encyclopedia’ was going to press.”

By Michael C. Fu

The making of ‘EORMS 3e’

So begins the third edition of the “Encyclopedia of Operations Research and Management Science,” published this fall by Springer. “EORMS 3e,” as it came to be called over its gestation, was Saul Gass’ last project, coming on the heels of (and overlapping with) the book (co-edited with Arjang Assad), “Profiles in Operations Research: Pioneers and Innovators,” which recounts the early history of the field through the eyes and lives of 43 individuals who were there from the birth of the profession. Together, the two works present and represent the field of operations research/management science (OR/MS), for which Saul served as chief ambassador for nearly 70 years. Saul was passionate, fervent and unrelenting in his belief that OR/MS could do good for humankind, and that good models – both quantitative and qualitative – could help solve many problems. He himself served as an ideal model to me as to what it means to be a scholar, as he continued to advocate for the field well past his retirement from the University of Maryland.

Brief History of the Encyclopedia

From the preface:

“The goal of the “Encyclopedia of Operations Research and Management Science” is to provide decision-makers and problem-solvers in business, industry, government and academia a comprehensive overview of the wide range of ideas, methodologies and synergistic forces that combine to form the preeminent decision-aiding fields of operations research and management science (OR/MS). The impact of OR/MS on the quality of life and economic well being of everyone is a story that deserves to be told in its full detail and glory. The “Encyclopedia of Operations Research and Management Science” is the prologue to that story.”

The “Encyclopedia of Operations Research and Management Science” traces its origins back to the early 1990s. The first edition was published in 1996 by Kluwer Academic Publishers, co-edited by Saul Gass and Carl Harris, with the intended audience being “anyone concerned with the science, techniques and ideas of how one makes decisions.” From the beginning there were three categories of entries: “dictionary” entries, mostly written by the editors; shorter articles, authored either by one of the editors or an outside expert; and full-length articles written by leading researchers in the field, such as Fred Hillier on linear programming, Dan Heyman on queueing theory and Tom Magnanti on network optimization. The second “Centennial” edition, also published by Kluwer, added 28 new articles and was published in 2001 shortly after Carl passed away on April 25, 2000. The third edition published by Springer has more than 1,200 entries, of which approximately are 270 full-length articles (the line between a full-length article and a shorter authored article is not hard and fast).

The target readership has been from the beginning two-fold: OR/MS researchers, practitioners, and students; and general scientists, mathematicians, economists, and other social scientists. The intent has to been for the work to serve both as a reference to those already in the field and as an entry into the wonderful world of OR/MS to those outside the field who are interested in learning about and/or using its rich palette of ideas, concepts, models, and methodologies. “Thus, the articles are designed to serve as initial sources of information for all such readers, with special emphasis on the needs of students.”

I wrote two of the new articles for the second edition and was already a big fan of the “Encyclopedia” when Saul approached me in 2007 about co-editing a third edition. I accepted his invitation without hesitation. The original contracted target date for submitting all of the materials of the third edition to the publisher was Sept. 30, 2010. As might be expected with such an ambitious undertaking, we encountered many twists and turns along the way, starting on May 10, 2007 when Saul sent an e-mail to the publishers proposing a third edition with me as new co-editor to Nov. 10, 2013 when I delivered published copies of the “Encyclopedia” to Saul’s widow Trudy.

What’s New for the Third Edition

The growth in the size of the “Encyclopedia” has been from approximately 750 pages for the first edition to 900 pages for the second to 1,650 pages for the third. Due to the increase, the third edition includes two volumes. The first two Kluwer editions have both a table of contents and an index, but Springer insisted on its standard encyclopedia format for the third edition, which includes neither a table of contents nor an index. However, a darkened “tabbing” allows readers to view the transition of entries from one letter to the next, so it can be useful for locating a particular entry fairly quickly, although there is no way of knowing a priori whether or not that particular entry even exists in the volume. The tabbing does reveal, however, in a visually obvious manner, that “C” entries occupy the most pages in Volume 1, whereas “S” holds that honor in Volume 2.

Every old entry was re-read by Saul and/or myself and updated as needed. A new feature for the dictionary items in the third edition is the addition of seminal references for some entries. Since the publication of the second edition, the Internet and World Wide Web have become ubiquitous sources of information, e.g., Wikipedia; however, due to the transient nature of page content, Saul was adamant on not including URLs in articles, so he had these removed and replaced with an informal reference to the World Wide Web.

Whereas the second edition added 28 new articles, the third edition saw the addition of 47 new full-length articles (several of these were shorter entries in previous editions; see accompanying sidebar story). These new articles can be roughly categorized as follows:

  • Important missing areas: convex optimization, differential games, global optimization
  • Expanded or rewritten replacement entries: community O.R., fuzzy sets, systems and applications; health care management; influence diagrams; Lagrangian relaxation; petroleum refining (replacing petro-chemical industry); quadratic assignment problem; sensitivity analysis; simulated annealing
  • Articles expanding upon other existing entries: air traffic management (airline industry O.R.), complementarity applications (complementarity problems), decision analysis practice (decision analysis), healthcare strategic decision-making (health care management/systems)
  • Completely new topics: agent-based simulation; approximate dynamic programming; business intelligence; closed-loop supply chains; combinatorial auction theory; computational biology; conditional value at risk; critical systems thinking; data warehousing; deep uncertainty; digital music; disaster management; disease prevention, detection and treatment; financial engineering; flexible manufacturing systems; heuristics; hit-and-run methods; knowledge management; Markov chain Monte Carlo; metaheuristics; open-source software (and COIN-OR); rare event simulation; regenerative simulation; response surface methodology; revenue management; sample average approximation; service science; societal complexity; statistical ranking and selection; stochastic approximation; stochastic input model selection

The latter two categories reflect developments in methodologies – with a clear emphasis on computation and simulation – and application areas from healthcare to finance to supply chain management.

Further Personal Reflections

Saul Gass passed away on March 17.

Saul Gass passed away on March 17.

Until the illness that finally sidelined him less than a year before his passing, Saul was still running miles on a daily basis (at age 86), so it was only fitting that the 5K Memorial Fun Run was resurrected in his honor at the recent Minneapolis INFORMS National Meeting. Saul would have been ecstatic. At the INFORMS meeting, Bruce Golden, Ed Wasil, Arjang Assad and I organized two sessions in Saul’s honor, and I spoke about the “Encyclopedia,” with the following personal reflections in PowerPoint:

  • I first saw Saul in person from afar in the spring of 1988 at the podium of the Washington Hilton Hotel. He was general chair of the 25th TIMS/ORSA Joint National Meeting delivering the welcoming remarks; I was a Ph.D. student in the audience attending my first O.R. conference.
  • I joined the faculty of Maryland fall 1989, and Saul was there with a friendly welcoming smile. He was always supportive when I was department seminar coordinator without a budget, helping me round up local speakers or alerting me when someone was passing through town who might be willing to give a talk.
  • I nominated Saul for University Distinguished Scholar-Teacher (1998), because I felt he epitomized the award.
  • One of my greatest joys at Maryland was when Bruce Golden, Frank Alt and I organized Saul’s 80th birthday celebration in 2006 (sponsored by our department in the Maryland Business School).
  • Though separated by more than a generation in age, I felt a special kinship with Saul, as we shared both the same Chinese and Western zodiac signs (tiger & fish, respectively), and we lived in the same town (Potomac; the only two in our department living there at the time), and our children attended the same middle and high schools, albeit more than a generation apart.
  • I last spoke with Saul on his 87th birthday (Feb. 28). Even at that time he mentioned the “Encyclopedia.”
  • I remember receiving the call informing me of his passing on March 17, as I was in Milan, Italy, and it was snowing (because of the time change, it was actually March 18 in the United States).

I grew up reading the “World Book Encyclopedia,” and I still have my 22-volume complete set of the 1972 edition (which my son enjoyed reading, too, until he discovered the Internet and YouTube). To co-edit an encyclopedia for my profession is something I never would have dreamed of then, and to be able to share such an undertaking with someone as special as Saul Gass is truly a dream come true, albeit with a bittersweet ending. Saul intended to write an article in OR/MS Today about “EORMS 3e” once it was published, so this one is for him.

Michael C. Fu ( is Ralph J. Tyser of Management Science in the Department of Decision, Operations & Information Technologies in the Robert H. Smith School of Business, with a joint appointment in the Institute for Systems Research, A. James Clark School of Engineering, all at the University of Maryland, College Park.


EORMS 3e adds 47 new articles  

EORMS 3e adds 47 new articles

Forty-seven full-length articles on the following topics were added to the third edition:
•     Agent-Based Simulation
•    Air Traffic Management
•     Approximate Dynamic Programming
•     Business Intelligence
•     Closed-loop Supply Chains
•     Combinatorial Auction Theory
•     Community O.R.
•     Complementarity Applications
•     Computational Biology
•     Conditional Value at Risk
•     Convex Optimization
•     Critical Systems Thinking
•     Data Warehousing
•     Decision Analysis Practice
•     Deep Uncertainty
•     Differential Games
•     Digital Music
•     Disaster Management
•     Disease Prevention, Detection and Treatment
•     Financial Engineering
•     Flexible Manufacturing Systems
•     Fuzzy Sets, Systems and Applications
•     Global Optimization
•     Health Care Management
•     Health Care Strategic Decision-Making
•     Heuristics
•     Hit and Run Methods
•    Influence Diagrams
•     Knowledge Management
•     Lagrangian Relaxation
•     Markov Chain Monte Carlo
•     Metaheuristics
•     Open Source Software (and COIN-OR)
•     Petroleum Refining
•     Quadratic Assignment Problem
•     Rare Event Simulation
•     Regenerative Simulation
•     Response Surface Methodology
•     Revenue Management
•     Sample Average Approximation
•     Sensitivity Analysis
•     Service Science
•     Simulated Annealing
•     Societal Complexity
•     Statistical Ranking and Selection
•     Stochastic Approximation    
•     `Stochastic Input Model Selection