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 investigate the impact of sickness absenteeism on productivity by using rich longitudinal matched employer-employee data on Belgian private firms. We deal with endogeneity, which arises from unobserved firm heterogeneity and reverse causality, by applying a modified version of the Ackerberg...