Economic stagnation, fixed factors, and policy thresholds

An endogenous growth model with fixed factors predicts that countries will stagnate if policies pass a threshold; initial income does not affect whether a country stagnates. For growing countries, the model has transitional dynamics where growth first accelerates and then decelerates as income rises. The data confirm these predictions: a probit equation predicts well whether countries stagnate as a function of policies but not of income, a truncated regression for growing countries shows a 'hump-shaped' relation between initial income and subsequent growth and equality of coefficients on income and other variables between the stagnation and growth regimes is rejected.