Essays on migration and diversity, tariff aggregators and the productivity of banking systems

My dissertation consists of three essays: the first essay analyzes the effect of social capital on migration, using a general equilibrium model; the second essay derives the properties of different tariffs aggregators and uses them to estimate the welfare impacts of trade liberalization; the third essay estimates commercial bank efficiency in Central and Eastern Europe.;Migration policy tends to favor homogeneity. However, there is a preference for importing those skills that are in relatively short supply. What are the welfare implications for natives of absorbing these different types of migrants? This paper examines these issues in a general equilibrium model with social capital. We find that there are three equilibrium solutions: an internal one with half the population of each country migrating to the other country, and two corner solutions where everyone ends up in one of the two countries. Either of the two corner solutions maximizes world welfare. Also, trade and migration are not equivalent if social capital is present. Welfare increases with free trade and is higher than under the internal migration solution and lower than under the corner solutions.;The use of traditional trade-weighted average tariffs biases the estimated welfare benefits of trade reform downwards. I analyze the tariff aggregators proposed by Bach and Martin (1996) and show that for the tariff revenue aggregator there are multiple uniform tariffs that yield the same revenue. I consequently redefine the tariff revenue aggregator. I derive the theoretical properties of the expenditure and tariff revenue aggregators, and under certain assumptions, develop closed form solutions for the expenditure and tariff revenue aggregators. Finally, I show that the trade-weighted average tariff is lower than the tariff revenue aggregator and the latter is lower than the expenditure aggregator.;Banking sectors in Transition economies have experienced major transformations throughout the 1990's. I estimate the indicators of commercial bank efficiency by applying a version of Data Envelopment Analysis (DEA) to bank-level data from a wide range of Transition countries. I further explain the differences in the efficiency of financial institutions across countries using a variety of macroeconomic, prudential and institutional variables.