Consequentialism is a moral philosophy that maintains that the moral worth of an action is determined by the consequences it has for the welfare of a society. Consequences of model design are a part of the model lifecycle that is often neglected. This paper investigates the issue using system dynamics modeling as an example. Since a system dynamics model is a product of the modeler’s design decisions, the modeler should consider the life cycle consequences of using the model. Seen from (...) a consequentialist perspective, the consequences of policies developed from system dynamics models determine the model’s moral value. This concept is explored by discussing model uncertainty from an engineering perspective. In this perspective, the ethical considerations shift from the behavior of the modeler to the model itself and the model’s inherent uncertainty. When the ethical considerations are taken away from the modeler and directed to what the model does, the ethical boundaries extend beyond the proximity of the model. This discussion renews the ethics conversation in system dynamics by considering this shift in philosophical perspective, and investigates how consequentialist moral philosophy applies to the modeling process and in communicating with decision-makers. A model of social assistance in Norway in the context of immigration pressures illustrates some possibilities for addressing these ethical concerns. This paper argues for an ethical framework, or at the very least, an ethical conversation within the field of system dynamics.Article first published online: 25 FEB 2017. (shrink)