Do Employees’ Sickness Absences React to a Change in Costs for Firms? Evidence from a Natural Experiment

We analyse the impact of a social security reform that changed the costs incurred by firms due to sickness absences. The reform abolished a compulsory insurance for firms, which insured them against the wages paid to sick blue‐collar workers. During the first year after its introduction, we estimate that the reform resulted in about 6.3 percent fewer sickness absences, and in about 8.6 percent fewer absence days. We do not find evidence for changes in hiring or firing, and we find only limited workforce composition changes. We do not find spillover effects on the absences of white‐collar workers. Robustness checks confirm these results

Firms' Moral Hazard in Sickness Absences

Sick workers in many countries receive sick pay during their illness-related absences from the workplace. In several countries, the social security system insures firms against their workers' sickness absences. However, this insurance may create moral hazard problems for firms, leading to the inefficient monitoring of absences or to an underinvestment in their prevention. In the present paper, we investigate firm' moral hazard problems in sickness absences by analyzing a legislative change that took place in Austria in 2000. In September 2000, an insurance fund that refunded firms for the costs of their blue-collar workers' sickness absences was abolished (firms did not receive a similar refund for their white-collar workers' sickness absences). Before that time, small firms were fully refunded for the wage costs of blue-collar workers' sickness absences. Large firms, by contrast, were refunded only 70% of the wages paid to sick blue-collar workers. Using a difference-in-differences-in-differences approach, we estimate the causal impact of refunding firms for their workers' sickness absences. Our results indicate that the incidences of blue-collar workers' sicknesses dropped by approximately 8% and sickness absences were almost 11% shorter following the removal of the refund. Several robustness checks confirm these results.absenteeism, moral hazard, sickness insurance

Firms’ moral hazard in sickness absences

Sick workers in many countries receive sick pay during their illness- related absences from the workplace. In several countries, the social security system insures firms against their workers’ sickness absences. However, this insurance may create moral hazard problems for firms, leading to the inefficient monitoring of absences or to an underinvestment in their prevention. In the present paper, we investigate firms’ moral hazard problems in sickness absences by analyzing a legislative change that took place in Austria in 2000. In September 2000, an insurance fund that refunded firms for the costs of their blue-collar workers’ sickness absences was abolished (firms did not receive a similar refund for their white-collar workers’ sickness absences). Before that time, small firms were fully refunded for the wage costs of blue- collar workers’ sickness absences. Large firms, by contrast, were refunded only 70% of the wages paid to sick blue-collar workers. Using a difference-in-differences-in-differences approach, we estimate the causal impact of refunding firms for their workers’ sickness absences. Our results indicate that the incidences of blue-collar workers’ sicknesses dropped by approximately 8% and sickness absences were almost 11% shorter following the removal of the refund. Several robustness checks confirm these results.absenteeism, moral hazard, sickness insurance

Firms’ moral hazard in sickness absences

Sick workers in many countries receive sick pay during their illness- related absences from the workplace. In several countries, the social security system insures firms against their workers’ sickness absences. However, this insurance may create moral hazard problems for firms, leading to the inefficient monitoring of absences or to an underinvestment in their prevention. In the present paper, we investigate firms’ moral hazard problems in sickness absences by analyzing a legislative change that took place in Austria in 2000. In September 2000, an insurance fund that refunded firms for the costs of their blue-collar workers’ sickness absences was abolished (firms did not receive a similar refund for their white-collar workers’ sickness absences). Before that time, small firms were fully refunded for the wage costs of blue- collar workers’ sickness absences. Large firms, by contrast, were refunded only 70% of the wages paid to sick blue-collar workers. Using a difference-in-differences-in-differences approach, we estimate the causal impact of refunding firms for their workers’ sickness absences. Our results indicate that the incidences of blue-collar workers’ sicknesses dropped by approximately 8% and sickness absences were almost 11% shorter following the removal of the refund. Several robustness checks confirm these results.absenteeism, moral hazard, sickness insurance

Using Answer Set Programming for pattern mining

Serial pattern mining consists in extracting the frequent sequential patterns from a unique sequence of itemsets. This paper explores the ability of a declarative language, such as Answer Set Programming (ASP), to solve this issue efficiently. We propose several ASP implementations of the frequent sequential pattern mining task: a non-incremental and an incremental resolution. The results show that the incremental resolution is more efficient than the non-incremental one, but both ASP programs are less efficient than dedicated algorithms. Nonetheless, this approach can be seen as a first step toward a generic framework for sequential pattern mining with constraints.Comment: Intelligence Artificielle Fondamentale (2014

On extended Kalman filters with augmented state vectors for the stator flux estimation in SPMSMs

The demand for highly dynamic electrical drives, characterized by high quality torque control, in a wide variety of applications has grown tremendously during the past decades. Direct torque control (DTC) for permanent magnet synchronous motors (PMSM) can provide this accurate and fast torque control. When applying DTC the change of the stator flux linkage vector is controlled, based on torque and flux errors. As such the estimation of the stator flux linkage is essential. In the literature several possible solutions for the estimation of the stator flux linkage are proposed. In order to overcome problems associated with the integration of the back-emf, the use of state observers has been advocated in the literature. Several types of state observers have been conceived and implemented for PMSMs, especially the Extended Kalman Filter (EKF) has received much attention. In most reported applications however the EKF is only used to estimate the speed and rotor position of the PMSM in order to realize field oriented current control in a rotor reference frame. Far fewer publications mention the use of an EKF to estimate the stator flux linkage vector in order to apply DTC. Still the performance of the EKF in the estimation of the stator flux linkage vector has not yet been thoroughly investigated. In this paper the performance of the EKF for stator flux linkage is studied and simulated. The possibilities to improve the estimation by augmenting the state vector and the consequences of these alterations are explored. Important practical aspects for FPGA implementation are discussed

On the stator flux linkage estimation of an PMSM with extended Kalman filters

The demand for drives with high quality torque control has grown tremendously in a wide variety of applications. Direct torque control (DTC) for permanent magnet synchronous motors can provide this accurate and fast torque control. When applying DTC the change of the stator flux linkage vector is controlled. As such the estimation of the stator flux linkage is essential. In this paper the performance of the Extended Kalman Filter (EKF) for stator flux linkage estimation is studied. Starting from a formulation of the EKF for isotropic motors, the influence of rotor anisotropy and saturation is evaluated. Subsequently it is expanded to highly isotropic motors as well. In both cases the possibilities to add parameter estimations are evaluated