Models for Responsibility Assignment

Responsibility assignment modelling is concerned with developing a picture of how the responsibilities in a socio-technical system are distributed across the different automated elements and actors in that system. At this stage, we are not concerned with the details of the responsibilities themselves, nor with what the actors in the system have to do to discharge these responsibilities. Rather, a responsibility model presents a succinct picture of 'who is responsible for what' that can be used to identify responsibilities that have not been assigned, responsibilities that have been misassigned and actors in the system who may be overloaded with responsibilities. We argue that these models have a role to play in identifying sources of undependability in a system. They can be used to help identify requirements that are inconsistent with the responsibility structures and to design robust and reliable operational processes. The primary use of responsibility assignment models is to serve as a basis for facilitating discussions on how responsibilities are distributed in an existing system and for planning the responsibility structure of new systems. In any system, there is some flexibility over 'who does what' and individual responsibilities are always subject to negotiation. By making responsibilities explicit, a responsibility assignment model allows designers, users and managers to develop a shared understanding of the responsibility structure in a system. This helps designers understand who needs what information and when they need it. In addition, the responsibility assignment model may be a useful supporting mechanism for identifying possible responsibility vulnerabilities in a system. Responsibility negotiation occurs during the specification and design phases of a socio-technical system. The system designers must negotiate with stakeholders to decide how the responsibilities associated with the system are distributed. Clearly, there are trade-offs to be made between automated and manual tasks. However, issues such as organisational structures and politics also affect the distribution of responsibilities. Responsibility renegotiation occurs when some of the actors in a system renegotiate their assigned responsibilities so that the distribution of responsibilities in the system is changed. This may be required because the organisational structure has changed, because some actors are over or under-loaded, because of changes in the people in a system, or because of new responsibilities that emerge as a system is deployed and used. The role of a