“…Moreover, most of the endogenous growth models mentioned above suffer from the "scale effect," meaning that the steady-state growth rate increases with the size (scale) of the economy, as indexed, for example, by population. 3 To breach this gap, the contribution of our work is twofold: first, we extend the Barro (1990) model, in which the engine of growth is productive public expenditure, by allowing for both endogenous labor supply (as in Turnovsky, 2000) and endogenous population (as in Barro & Becker, 1989;Barro, 1988 andRenström, 2012;Renström & Spataro, 2019) in one encompassing model. Second, in this scenario, we analyze the second-best optimal tax structure.…”