The paper argues that economic integration causes problems for the labor market of high-wage countries due to cross-border labor mobility and the accompanying increase in labor supply. Empirical evidence is provided from an analysis of regional labor market effects of German re-unification. In...

In this paper we evaluate the impact of a major school reform, that took place in the 1950s in Sweden, on educational attainment and earnings. The reform, which has many common elements with reforms in other European countries including the UK, consisted of increasing compulsor schooling,...

The paper argues that economic integration causes problems for the labor market of high-wage countries due to cross-border labor mobility and the accompanying increase in labor supply. Empirical evidence is provided from an analysis of regional labor market effects of German re-unification. In...

This paper reports on a re-evaluation of the German health care reform of 1997. A previous evaluation found a limited effect of a 4.4 percent reduction of the number of doctor visits in a sample of pharmacy customers. The re-evaluation based on a representative household survey, the German...

Difference in differences (DID) require that the treatment rate is equal to 0% in the control group and during period 0 (no “always takers”) and to 100% in the treatment group in period 1 (no “never takers”). Sometimes, treatment rate increases more in the treatment than in the control...

In this paper we survey methods to control for regression model error that is correlated within groups or clusters, but is uncorrelated across groups or clusters. Then failure to control for the clustering can lead to understatement of standard errors and overstatement of statistical...