Large group decision making: Creating Decision Support Approaches at Scale (1st ed.) Carrascosa I. Springer Publishing Company, Incorporated, 2018. 140 pp. Type: Book (978-3-030010-26-3)

Decision Support (H.4.2); General (H.4.0...); Information Systems Applications (H.4) Decision-making is a daily task everyone uses to do. Decisions are being taken every time for example in the morning by going to work, everywhere like at the market, at lunch, at dinner, at home, at work, etc. We will though face our entire life situation where we need to make or take decisions, which can impact our whole life. For example, as a manager, you are asked to maximize the benefit of the firm or reduce or prevent loss. Your decision could be to delete some jobs. The impact of this decision is not predictable.

A decision can be individual or group decision. A group decision-making process is more complex than the individual decision-making process. Though, the larger the group, the more complex decision-making process becomes because group decision-making is actually consensus-based. And consensus finding is complex and can take longer.

The book entitled “Large Group Decision Making – Creating Decision Support Approaches at Scale” covers along six (06) chapters the basics and fundamental rules of the individual, group, and large group decision-making process. The author has pointed out along this book consensus as for the fundamental rule supporting(large) group decision-making. Consensus must be reached and accepted or adopted by everyone or the majority of the group members. The author presents different ways to reach a consensus in a group regarding the group size, the expertise level of group members, etc. The author has concisely explained how experts can reach a consensus,regardless of the decision is made by a minority or not. he further discusses how the consensus process is carried out and how it could be supported by a majority. The author presents different examples of decision-making from the real world and discusses each of them. However, I miss an important example, namely the behavior of political parties members who individually accept following a consensus of the central committee to support the voting of the party candidate even if the candidate is not largely accepted in the party basis. And another example is the way hooligans quickly reach consensus after their favorite team loses a football game. I can remember many hooligan scenes where only two or three members make a decision and the decision finds quickly consensus among the group. I will appreciate knowing how such ad-hoc consensus is made and many people accept to follow such action regardless of how dangerous this action is

I appreciate the book-chapter 4 as well as chapter 2. Chapter 4 succinctly describes the different categories of large group decision-making (LGDM) and make clear what LGDM is and how decision are consensually taken or how a decision can be proven to be made on large consensus. Chapter 2 provides with the backgrounds of what consensus is, how this is built, and how this is measured. The chapter is very interesting. I verify the mathematical formulae and appreciate them. Chapter 5 discusses some LGDM implementation in the real world. According to my background, I appreciate the two following sections: (1) social LGDSS and (2) Emergency LGDM.

The weakness of this book is in its structure, I mean how the sequence of the chapters is built. Each chapter, individually considered, is well structured and is presented in a clear linguistic style. However, I think the book should better be structured and thus would be more judicious for the readers if the author takes the readers gradually through the book by beginning with the introduction as he does, and then following by the state-of-the-art by discussing the conducted literature review on large group decision-making (chapter 4). So the reader would get into the “what is going on, in the scene” and from there he will start asking about what large group decision-making is. Only then, the central point, a decision consensus, within a (large) group decision-making process could be presented (I mean chapter 2). Scaling up a group decision-making process (chapter 3) would then show the way to get consensus in a larger group by decision making. Chapter 5 presents the application of large group decision making in the real world and chapter 6 concludes the book. I suggest the readers read the book in the following sequence: chapter 1, following by 4, then 2, 3, 5, and 6.

Besides the minor weakness noted in the previous section, the book is readable, fluid, understandable. Though, the reader needs to have a minimum of mathematical background to follow the demonstrations by means of formulae. I recommend this book for researchers working on operational research, people with decision-making role, politicians, as well as the larger public even if they lack mathematical background.