Score contribution per author:
α: calibrated so average coauthorship-adjusted count equals average raw count
The growth of many cities and industries differs, with some growing slowly and others experiencing rapid change—i.e., rushes. To explain these differences and explore the mechanisms of growth, we develop a model centered on a new trade-off between time-varying fundamentals and time-invariant – but rank-dependent – opportunities. Early population flows depend on the opportunities new entities provide, whether from available land in cities or the accumulation of entrepreneurship human capital in firms. Our model can explain the existence of rushes and their size. We provide suggestive empirical evidence on city- and industry growth consistent with the model’s predictions.