The thesis consists of three papers, summarized as follows.        "The Determinants of Labour Market Institutions: A Panel Data Study"    This paper analyses the argument that labour market institutions can be thought of as devices for social insurance. It investigates the hypotheses that a country's exposure to external risk and ethnic fractionalisation are correlated with labor market institutions. Extreme bounds analysis with panel data of fourty years indicates that countries that are more open to international trade have stricter employment protection, strong unions, and a more coordinated wage bargaining process. Moreover, there is evidence that union density is negatively associated with the degree of ethnic fracationalisation.  "Why do Some Studies Show that Generous Unemployment Benefits Increase Unemployment Rates? A Meta-Analysis of Cross-Country Studies"    This paper investigates the hypothesis that generous unemployment benefits give rise to high levels of unemployment by systematically reviewing 34 cross-country studies. In contrast to conventional literature surveys, I perform a meta-analysis which applies regression techniques to a set of results taken from the existing literature. The main finding is that the choice of the primary data and estimation method matter for the final outcome. The control variables in the primary studies also affect the results. "The Effects of Trade on Unemployment: Evidence from 20 OECD countries"    This study empirically investigates if international trade has an impact on aggregate unemployment in the presence of labour market institutions. Using data for twenty OECD countries for the years 1961-2008, this study finds that an increase in trade leads to higher aggregate unemployment as it interacts with rigid labour market institutions, whereas it may reduce aggregate unemployment if the labour market is characterised by flexibility. In a country with the average degree of the labour market rigidities, an increase in trade has no significant effect on unemployment rates.