When studying particular subgroups of a population, like for instance lone parents, the econometrician typically has few observations at hand. In such a situation, it is vital to take advantage of any valid complementary information that may be available. In this paper we illustrate, for the...

We analyze the performance of firms in the German business-related services sector. A quarterly business survey provides the panel data base of our study. Firm performance is measured by the survey respondents' ordinal indication of their changes in total sales. We use a firstorder Markov chain...

We present a new method for imposing and testing concavity of a cost function using asymptotic least squares, which can easily be implemented even for cost functions which are nonlinear in parameters. We provide an illustration on the basis of a (generalized) Box-Cox cost function with six...

Gerlach and Stephan (1994) proposed a test based on the idea that the wage premium, the part of the wage which is not explained by the stock of human capital, should help predict variables such as career expectations (quit, change occupation, leave the labour force) and some job characteristics...