Essays in Heterogeneity, Irreversibility and Aggregate Fluctuations

Essays on Heterogeneity, Irreversibility and Aggregate Fluctuations explores the connections between micro structure and technologies available to the agents operating in the economy and the dynamic of aggregate output and productivity. The thesis aims at further understanding the linkages between investment decisions of heterogeneous firms, the industry structure, and the aggregate dynamic of the economy. The hypothesis explored in this dissertation is that the dynamic of the industry structure, the patterns of selection of firms and investment within an industry bear information as of the efficiency with which the economy operates. The thesis consist of three essays organized in chapters. Chapter I, Efficiency with Equilibrium Marginal Product Dispersion and Firm Selection investigates conditions under which reductions in marginal product of capital dispersion induce Pareto improving allocations. The main result is that it is possible for allocations that display higher marginal product dispersion to be closer to the efficient one than allocations with lower marginal product dispersion. Chapter II, Industry Dynamics, Investment and Business Cycles investigates the quantitative implications of irreversibilities in investment for aggregate productivity.The main result of the essay is that for a calibrated economy to the US manufacturing sector, efficiency losses associated to firm selection are quantitatively more important than those associated to lower equilibrium dispersion in marginal products, i.e. capital reallocation. Chapter III, Aggregate Fluctuations and the Industry Structure of the US Economy documents changes in the input matrix of the US economy, and analyzes its implications for the relevance of sector specific and neutral shocks in aggregate fluctuations. The main finding is that an economy where the input output entries are allowed to fluctuate as in the data generates larger amplification of shocks and a stronger role for neutral shocks than a comparable economy with a fixed input output structure