SOFTWARE PROCESS IMPROVEMENT AND PRACTICE Softw. Process Improve. Pract. 2007; 12: 65–79 Published online 27 September 2006 in Wiley InterScience (www.interscience.wiley.com) DOI: 10.1002/spip.301 Defining Business Process Flexibility with the Help of Invariants Research Section Gil Regev, 1 * ,† Ilia Bider 2 and Alain Wegmann 1 1 Ecole Polytechnique F´ ed´ erale de Lausanne (EPFL), School of Computer and Communication Sciences, CH-1015 Lausanne, Switzerland 2 IbisSoft, Stockholm, Sweden Enterprise survival is about maintaining an identity that is separate from other enterprises. We define flexibility as the ability to change without losing identity. The identity of an enterprise can be analyzed as a set of norms and beliefs about these norms held by its stakeholders, such as customers, employees, suppliers, and investors. Business processes and their support systems maintain invariants that are the result of compromises between the often conflicting norms and beliefs of these stakeholders. We formalize these invariants as values in a state space. Identifying a minimum set of invariants provides a basis for defining flexible processes and support systems. We illustrate the use of this framework with production business process support (BPS) systems. Copyright  2006 John Wiley & Sons, Ltd. KEY WORDS: business process; flexibility; stability; invariant; regulation 1. INTRODUCTION Enterprise survival often hinges on the fit between the enterprise’s position in its environment on the one hand and its business processes and their supporting systems on the other. Flexibility is an essential property for the maintenance of this fit in changing environments (Knoll and Jarvenpaa 1994). Changes within the enterprise and in the enter- prise’s environment often introduce misfits between the enterprise and its environment. Business pro- cesses and business process support (BPS) systems need to be flexible so that changes can be made to them to correct these misfits. ∗ Correspondence to: Gil Regev, Ecole Polytechnique F´ ed´ erale de Lausanne (EPFL), School of Computer and Communication Sciences, CH-1015 Lausanne, Switzerland. † E-mail: Gil.regev@epfl.ch Copyright  2006 John Wiley & Sons, Ltd. Flexibility is usually thought of as the capability to change. It may, however, be useful to analyze flexi- bility from the opposite dimension of stability. From this perspective, we argue that to change something, that something first needs to exist, i.e. without prior existence, change is not possible. Furthermore, to exist, that something needs to maintain a set of fea- tures that is different from all other things in its environment. This set of features enables observers of the thing to define its identity. For example, for an enterprise to exist, it has to have some features that are different from other enterprises. These features constitute the enterprise’s identity in the eyes of its stakeholders. These features need to remain some- what stable in order for the enterprise to maintain its identity. From this point of view, existence is about nonchange, i.e. stability. To maintain the stability of these features in a changing environment, the enter- prise needs to continually adapt. Hence, there is no existence without change. Therefore, flexibility is the ability to continuously balance between change and stability without losing identity.