Nonlinearities in productivity growth: A semi-parametric panel analysis

► We study the productivity growth when countries are close to technology frontiers. ► We estimate reduced and structural forms of TFP growth using a semi-parametric generalized additive model for panel data. ► The convexity between productivity growth and proximity depends on the measurement of the frontier. ► The relation between productivity growth and human capital shows a high degree of nonlinearity. ► International trade has a positive effect on productivity growth.