Oil shocks, output composition and labor demand

Previous empirical works suggest that oil shocks have an important effect on economic activity. However, the extent of this relationship cannot be easily explained with traditional one-sector macroeconomic models because oil makes up a small share of firms' costs. The first chapter of this thesis suggests that, beside its effect on aggregate marginal cost, oil price affects output composition and as a consequence, aggregate labor demand, in a way that has not been previously analyzed. The basic predictions of the model are consistent with the evidence for the US during the oil price hikes in the seventies and during the reduction of oil prices in the eighties. This study shows that changes in output composition are as important as changes in aggregate marginal cost to explain the evolution of the aggregate labor demand during the seventies and eighties.;The other two chapters of this thesis analyze the relationship between competition, sales agents and turnover. Sales agents promote firms' characteristics, inform customers, and facilitate both transactions and switches among products. However, under certain circumstances, sales agents can induce (through gifts) customers to switch among products even when it is not socially efficient, thereby increasing the industry cost.;The Chilean fully funded pension system fits this last model. In 1995 there was more than one sales agent per two hundred affiliates in the system, accounting in this year for more than 33 percents of total costs. During this same year, consumer turnover between Pension Fund Administrators (PFAs) was more than 50 percent, or 1.5 million workers. Surprisingly, this huge turnover was not associated with important changes in PFA market shares. Chapter three shows than in this market more than three quarter of total turnover is related with sales agents, and only 25 percent out of this turnover related with sales agents is efficient from a social point of view. In other words, sales agents through gifts are allowing firms to discriminate between current and potential customers, and as a consequence are inducing an endogenous turnover.