In Defence of the Endogenous Growth Theory: "Conditional" and "Unconditional" Convergence in Two-Country AK Models

Recent studies on cross-country (per capita) income inequality have found evidence for 'unconditional' convergence, and have interpreted this finding as a data rejection for AK growth models. This paper shows that a two-country version of the AK model with learning-by-doing externalities, extended to include international knowledge transfer, is: (i) consistent with the finding of 'unconditional' convergence that characterizes the world economy since mid 1980s; (ii) more effective than Neoclassical growth models to predict all types of convergence/divergence patterns that the empirical growth economists have documented in almost forty years of literature.