In the paper is considered identification of coefficients in equations explaining a continuous variable, say the number of sickness absence days of an individual per year, by cohort, time and age, subject to their definitional identity. Extensions of a linear equation to polynomials, including...

Identification of equations explaining a continuous variable, e.g., the length of sickness absence spells, by age, cohort and time (ACT), subject to their definitional identity is reconsidered. Various extensions of a linear equation to polynomials are explored. If no interactions between the...

We discuss a new approach to specifying and estimating ordered probit models with endogenous switching, or with binary endogenous regressor, based on copula functions. These models provide a framework of analysis for self-selection in economic well-being equations, where assigment of regressors...

High nonresponse rates have become a rule in survey sampling. In panel surveys there occur additional sample losses due to panel attrition, which are thought to worsen the bias resulting from initial nonresponse. However, under certain conditions an initial wave nonresponse bias may vanish in...

The German education system is organised in a federal system, i. e. each of the 16 Federal States is solely responsible for the supply and financing of the university places. Offering a suficient number of these places is important in achieving the aim of promoting academic education and...