Flexibility: a multi-disciplinary literature review and a research agenda for designing flexible engineering systems

Flexibility, despite its popularity, is not yet an academically mature concept - compared with optimality and robustness, for example. Flexibility is nevertheless recognised as a critical attribute of a system, a process, or an organisation; it is needed in order to cope with uncertainty and change, and implies an ability to change and adapt to a range of conditions. An interesting observation has been made that the concept of flexibility is today where the notion of quality was some 20 years ago, 'vague and difficult to improve, yet critical to competitiveness'. In this paper, we review the concept of flexibility as discussed in a number of academic disciplines that have grappled with this concept, and highlight the major themes, challenges, and limitations in each case. We analyse flexibility in the context of decision theory, real options, manufacturing systems, and engineering design. We also provide a critical assessment of the use and abuse of the word flexibility in the technical literature. Finally, we propose a series of research questions that can help transform flexibility into a quantifiable engineering attribute and grow this concept to the level of maturity of optimisation and robustness in system design.