Title: Essays on Macroeconomics
Description: This dissertation is a collection of three essays on macroeconomics, examining the sources of business cycles. In particular, we are interested in understanding how shocks propagate over the business cycle in both closed economy and open economy settings. The common approach we take in these chapters is to use both theory and data in a structural estimation based on a dynamic stochastic general equilibrium model. In the first chapter, motivated by the correlation of business cycles across countries, we provide a new empirical evidence about the role of common shocks in business cycles for small open economies. Specifically, we conduct a structural estimation of a small open economy real business cycle model featuring a realistic debt adjustment cost and common shocks. Using a novel dataset for 17 small developed and developing countries between 1900 and 2006, we find that common shocks are a primary source of business cycles, explaining nearly 50% of the output fluctuations over the last 100 years in small open economies.

The estimated common shocks capture important historical episodes such as the Great depression, the two World Wars and the two oil price shocks. Moreover, these common shocks are important for not only small developed countries but also developing countries. We point out the importance of our structural approach in identifying the sizable role of both productivity and other common shocks such as interest rate premium shocks. The reduced form dynamic factor model approach in the previous literature, which often assumes one type of common component, would predict only a third of the contribution estimated in the structural model. In the second chapter, we focus on the transmission from one country to another through international trade. First, we argue that while we observe substantial business cycle correlation across countries, especially among developed economies, most existing models are not able to generate strong transmission of shocks endogenously through international trade. In the framework of structural model, we show that the nature of such transmission depends fundamentally on the features determining the responsiveness of labor supply and labor demand to international relative prices.

We augment a standard international macroeconomic model to incorporate three key features: a weak short run wealth effect on labor supply, variable capital utilization, and imported intermediate inputs for production. This model can generate large and significant endogenous transmission of technology shocks through international trade. We demonstrate this by estimating the model using data for Canada and the United States with quasi-Bayesian methods. We find that this model can account for the substantial transmission of permanent U.S. technology shocks to Canadian aggregate variables such as output and hours documented in a structural vector autoregression. Transmission through international trade is found to explain the majority of the business cycle comovement between the United States and Canada while exogenous correlation of technology shocks is not important. In the third chapter, we turn to the sources of business cycles in a closed economy setting and analyzes the effects of news shocks, which are found to be an important driver of business cycles in the U.S. in the recent literature.

The innovation of this chapter is that we use data on expectations to inform us about the role of news shocks. This approach exploits the fact that news shocks cause agents to adjust their expectations about the future even when current fundamentals are not affected, therefore, data on expectations are particularly informative about the role of news shocks. Using data on expectations, we estimate a dynamic, stochastic, general equilibrium model that incorporates news shocks for the U.S. between 1955Q1 and 2006Q4. We find that the contribution of news shocks to output is about half of that estimated without data on expectations. The precision of the estimated role of news shocks also greatly improves when data on expectations are used. Moreover, the contribution of news shocks to explaining short run fluctuations is negligible. These results arise because data on expectations show that changes in expectations are not large and do not resemble actual movements of output. Therefore, news shocks cannot be the main driver of business cycles.