Jointness of growth determinants: Reply to comments by Rodney Strachan,Eduardo Ley and Mark F.J. Steel

This comment contrasts the jointness statistics proposed by Doppelhofer and Weeks ( 2009 ) with alternatives proposed by Strachan ( 2009 ) and Ley and Steel ( 2007 ). In contrast to the alternatives, our jointness statistic constitutes a formal test for dependence over the joint posterior distribution. The essential difference between our proposed measure and the alternatives is that our jointness measures uses the entire joint posterior distribution. We discuss differences in jointness, as well as inclusion and exclusion margins of the joint posterior distribution, and the impact on economic significance using the numerical examples given by Strachan ( 2009 ) and Ley and Steel ( 2009 ). Copyright © 2009 John Wiley & Sons, Ltd.     

Application of early risk detection concepts and methods to environmental health. A German feasibility study

Early risk detection is essential for being able to address the most important environmental health risk‐topics in a persistent and prospective manner. In support of the action programme “Environment and Health” (APUG) of the German Federal Ministry of Health and Social Security (BMGS) and the Federal Ministry for the Environment, Nature Conservation, and Nuclear Safety (BMU) which recommended that a detection and evaluation system for the timely recognition of emerging risk problems be developed, a qualitative feasibility study was commissioned. The results of this study are presented here and support the development of an early risk detection system based on the insights gained from the investigation of case studies and the differentiation and presentation of a risk typology, methods, tools, and suggested organizational processes.

The study has shown that early risk detection includes the identification, characterization, evaluation and dissemination of information on possible risks as well as the circumstances of appearance and distribution. The goal is the recognition of possible risks in order for risk management to be able to introduce swift and appropriate measures. Consequently, it can also serve as an instrument towards further development of a balanced and structured implementation of the precautionary principle in the environmental health policy.     

Spinoffs and clustering

Geographic clustering of innovative industries is associated with the entry and success of spinoff firms. We develop a model to explain the multiple empirical patterns regarding cluster growth and spinoff formation and performance, without relying on agglomeration externalities. Clustering naturally follows from spinoffs locating near their parents. In our model, firms grow and spinoffs form through the discovery of new submarkets based on innovation. Rapid and successful innovation creates more opportunities for spinoff entry and drives a region's growth. Our model provides baseline estimates of levels of agglomeration that can be attributed to this process of innovation and spinoff formation.     

Price-raising drug enforcement and property crime: a dynamic model

Price-raising drug enforcement suppresses drug use, but it is expensive and may increase property crime. This has led to contradictory recommendations concerning how drug enforcement should or should not be used. We reconcile these recommendations by incorporating the enforcement's effects on both drug use and on property crime within an optimal-control model that recognizes whether convicted drug-involved property offenders are merely incarcerated or whether they receive some form of drug treatment.