Disruption indices and their calculation using web-of-science data: Indicators of historical developments or evolutionary dynamics?

Science and technology develop not only along historical trajectories, but also as next-order regimes that periodically change the landscape. Regimes can incur on trajectories which are then disrupted. Using citations and references for the operationalization, we discuss and quantify both the recently proposed "disruption indicator" and the older indicator for "critical transitions" among reference lists as changes which may necessitate a rewriting of history. We elaborate this with three examples in order to provide a proof of concept. We shall show how the indicators can be calculated using Web-of-Science data. The routine is automated (available at http://www.leydesdorff.net/software/di/index.htm) so that it can be upscaled in future research. We suggest that "critical transitions" can be used to indicate disruption at the regime level, whereas disruption is developed at the trajectory level. Both conceptually and empirically, however, continuity is grasped more easily than disruption.