The difference between wages and wage potentials: Earnings disadvantages of immigrants in Germany

Immigrants in Germany have poor earnings performance relative to natives. Claiming that human-capital endowments determine earnings potentials rather than actual earnings, a stochastic earnings frontier is estimated and used to seek systematic differences between natives and migrants for GSOEP data for the year 2000. While empirical results clearly support the frontier assumption, natives and immigrants are surprisingly about the same with respect to the frontier. Assuming a half-normal distribution of the wage gap, on average, both groups transform a modest 84% share of their potential income into market earnings. This implies wage inequality can be attributed to human-capital differentials alone. The human-capital endowments of immigrants are largely determined by the very low percentage who have college degrees, their slow assimilation and zero-return on imported experience. The paper also tries to explain individual wage gaps, which are significantly decreased in married subjects raising families, but increased in employees in small- or medium-sized relative to larger firms. However, these variables only make minor contributions to the variance.