This analysis shows that multivariate generalizations to the classical Heckman (1976 and 1979) two-step estimator that account for cross-equation correlation and use the inverse Mills ratio as a correction-term are consistent only if certain restrictions apply to the true error-covariance...

In 1996 free choice of health insurers has been introduced in the German social health insurance scheme. Competition between insurers was supposed to increase efficiency. A crucial precondition for effective competition among health insurers is that consumers search for lower-priced health...

In the German wastewater sector, innovations are often regarded to be the key to both more efficient service provision and reduction of environmental and health-related problems. However, it is unclear what factors foster these innovations. One possible candidate factor is increased competition...

In Germany, hard coal has been subsidized for almost half a century. Despite the declining significance of hard coal production for the domestic labor market, the magnitude of subsidies increased until the middle of the last decade. In 1996, they peaked at Þ 6.7 bill.While German hard coal...

The question of whether two drugs namely alcohol and tobacco are used as complements or substitutes is of crucial interest if side-effects of anti-drug policies are considered. Numerous papers have empirically addressed this issue by estimating demand systems for alcohol and tobacco and...