Operational Research: methods and applications

This is the final version. Available on open access from Taylor & Francis via the DOI in this recordThroughout its history, Operational Research has evolved to include methods, models and algorithms that have been applied to a wide range of contexts. This encyclopedic article consists of two main sections: methods and applications. The first summarises the up-to-date knowledge and provides an overview of the state-of-the-art methods and key developments in the various subdomains of the field. The second offers a wide-ranging list of areas where Operational Research has been applied. The article is meant to be read in a nonlinear fashion and used as a point of reference by a diverse pool of readers: academics, researchers, students, and practitioners. The entries within the methods and applications sections are presented in alphabetical order. The authors dedicate this paper to the 2023 Turkey/Syria earthquake victims. We sincerely hope that advances in OR will play a role towards minimising the pain and suffering caused by this and future catastrophes

Strategic options development and analysis

Strategic Options Development and Analysis (SODA) enables a group or individual to construct a graphical representation (map) or a problematic situation, and thus explore options and their ramifications with respect to a complex system of goals or objectives. In addition the approach aims to help groups arrive at a negotiated agreement about how to act to resolve the situation. It is based upon the use of causal mapping – a formally constructed means-ends network. Because the map has been constructed using the natural language of the problem owners it becomes a model of the situation that is ‘owned’ by those who define the problem. The use of formalities for the construction of the model makes it amenable to a range of analyses encouraging reflection and a deeper understanding. These analyses can be used in a ‘rough and ready’ manner by visual inspection or through the use of specialist causal mapping software. Each of the analyses helps a group or individual discover important features of the problem situation. And these features facilitate agreeing a good solution. The SODA process is aimed at helping a group learn about the situation they face before they reach agreements. Most significantly the exploration through the causal map leads to a higher probability of more creative solutions and promotes solutions that are more likely to be implemented because the problem construction process is more likely to include richer social dimensions about the blockages to action and organizational change. The basic theories that inform SODA derive from cognitive psychology and social negotiation, where the model acts as a continuously changing representation of the problematic situation (a transitional object) – changing as the views of a person or group shift through learning and exploration. This chapter jointly written by two leading practitioner academics and the original developers of SODA, Colin Eden and Fran Ackermann, describe the SODA approach as it is applied in practice

Comparing discrete-event simulation and system dynamics: users' perceptions

This paper is the first of its type in that it provides an empirical study comparing the two simulation approaches of discrete-event simulation (DES) and system dynamics (SD). Prior comparison work is limited and mostly based on the authors' personal opinions. In the present work, the comparison is based on managers' (executive MBA students) perceptions of two simulation models of the same problem, one in DES and one in SD. The study found that there is no significant difference from the users' point of view between DES and SD in terms of model understanding and model usefulness. Some minor differences were found in terms of complexity and validity of the models, and the model results. The implications of our findings regarding model understanding, model complexity, model validity, model usefulness and model results are discussed

Supporting strategic conversations : the significance of a quantitative model building process

This paper reports on the use of a quantitative system dynamics simulation model building process that followed on from a ‘soft OR’ strategy making intervention with a top management team. The work was carried out for the Chief Constable and top team of a UK police force. The output of the ‘soft OR’ strategy making process provided the reason for, and so focus of, the simulation model. The focus of the strategic conversation was on exploring the tension between the supply of resources (in this case police officers) and the demands placed on those officers. The project involved a series of strategic conversations with members of the top team that were stimulated through the process of building a system dynamics model. The process was facilitated by two modellers—one focussing on managing the strategic enquiry, while the other considered the implications of the conversation for the construction of the system dynamics model. Through the process of gradually building the system dynamics model, a number of issues and lessons were raised for the development and delivery of effective strategy making and the strategic management of public organisations. In addition there were implications for operational research model building processes, especially when operating at senior levels and within a strategic context