In many disciplines, attention to the study of behavioural issues becomes important when their theoretical core has reached maturity. This has happened, for example, in economics, finance, accounting, and operations management. The development of the OR discipline is similar, as evidenced by the increasing attention that Behavioural OR (BOR) is receiving in the OR community. Those interested in studying behavioural issues within OR recognise that developing technically correct and valid models is not enough: a broader concern with designing an effective OR-supported intervention must always inform the modelling effort. Specifically, they share the belief that only by increasing our understanding of how behavioural factors enhance or hinder OR-supported interventions, can the practice of OR be improved and have greater impact in the real world.

The current momentum of the BOR movement in Europe is unmistakable. For example, we have witnessed the highly attended BOR sessions at IFORS 2014 (Barcelona) and EURO 2015 (Glasgow), as well as the high number of sessions scheduled at the forthcoming EURO 2016 (Poznan). Indeed, the BOR sessions have (or will) run throughout the entire duration of a conference. In addition, the recent
EJOR Special Issue on BOR, published in March 2016, attracted a high number of submissions. The resulting collection of papers in that issue covered a wide range of behavioural-related topics in OR (e.g. behaviour with models, modelling behaviour), used both experimental and field research methods, and cut across a number of approaches (e.g. decision analysis simulation, forecasting, problem structuring methods, system dynamics, optimisation). More recently, a BOR website portal was launched, and the first BOR Summer School hosted by Aalto University was successful with excellent feedback from participants. There is also an edited BOR book whose launch is scheduled for August 2016. All of these activities are a clear testimony of the closer attention that the European OR community is increasingly showing to the behavioural perspective. Noticeable within the emergent BOR community is a commitment to empirically examine what people actually do within a system or when engaged in OR-supported processes, and in the impact of these doings on the effectiveness of OR.

Against this background, it seems timely that a BOR European Working Group (EWG-BOR) is formed with a view to support the continuing development of an attractive, interdisciplinary and connected European BOR community. Such a group would be an ideal platform for strengthening the visibility and recognition of BOR research and researchers; for sharing the practical value and impact of BOR studies among OR academics, users, clients and sponsors; and for providing developmental opportunities for young European scientists and students. In addition, the proposed EWG-BOR would enable EURO to establish a new promising and distinctive area that is currently not being addressed by any other international OR society (e.g. INFORMS).

The purpose of the EWG-BOR is, therefore, to provide guidance to European OR academics, teachers and practitioners for developing effective OR-supported interventions by:

• Sharing behavioural-based explanations of the factors that shape the practice of modelling, model use, and model results communication;
• Fostering and strengthening collaboration opportunities between members of the Behavioural OR community; and,
• Offering training opportunities for developing skills for current and future generations of BOR scholars and students in the conduct of Behavioural OR studies.

The EWG-BOR has clear connections with some of the existing EWGs, but no single EWG fully covers our field. For example, part of the remit of the EWG on Group Decisions and Negotiation Support includes the study of behavioural factors in a group context, but our focus also covers the individual and organisational levels. We also have common interests with the active EWG on Decision Support Systems, particularly with regards to behavioural issues associated with the use of decision support systems (DSS). However, our focus on behaviour goes beyond DSS to include other aspects of OR such as modelling behaviour, dynamics of preference elicitation, facilitated modelling interactions, and communicating with models. We also have an interest on examining ethical and non-ethical behaviours in OR, a concern that is shared by the EWG in OR and Ethics. However our focus is mainly on studying these issues empirically rather than theoretically. Finally, although we also share common interests with the long-standing EWG on Multiple Criteria Decision Aiding, our behavioural focus cuts across a wider range of OR approaches, of which MCDA is only one.