Rankings and job market dynamics: a model of academic science

Among the many changes that have affected academic life in recent decades we draw attention to two: increasing collaboration in the production of knowledge, and the rising prominence of (automated) 'rankings' in the evaluation of individuals and institutions. In this paper, we build a model to address the effect of the latter in the presence of the former. Scientists collaborate to create new knowledge. Intra-department collaborations dominate, but cross-department knowledge flows are present in two forms: collegial links outside a department, and a job market whereby scientists can change departments. Rankings enter the model through the job market: they are parametrized to control the extent to which they are used to evaluate job candidates on the one side and job openings on the other side of the market. We find that when rankings are aggressively pursued, aggregate knowledge output is lower, and further, knowledge production at both individual and department levels is more stratified, or segregated. These effects can be mitigated by encouraging extra-department collaboration, but we observe that this strategy will erode the coherence (and purpose) of the department structures in which universities are currently organized.