Impairment of performance by alcohol and diazepam (author's transl)]

An investigation was carried out on the effect of the intake of diazepam and alcohol on simple performance tests. The combined administration of diazepam and alcohol led to an increase of the plasma diazepam concentration as compared to that obtained after diazepam without alcohol. Furthermore, after combined intake of diazepam and alcohol a decrease of performance was observed, that was significantly higher, than the effects obtained after either alcohol or diazepam alone. This impairment was especially noticeable duirng the first hour of the experiment, i.e. until the plateau of the diazepam plasma concentration was reached, while afterwards a correlation between diazepam plasma concentration and impairment of performance could not be established. The relevance of these findings for the interpretation of diazepam plasma concentrations in relation to the impairment of performance are discussed.     

On the Robustness and Validity of Groups

In response to Nagin's comment on our paper, Methodological Sensitivities to Latent Class Analysis of Long-Term Criminal Trajectories, we reconsider the robustness and validity of group-based approaches to criminal trajectories and introduce additional issues for future research. We emphasize the limitations of typological approaches and the dangers of reifying the idea of distinct offender groupings for research and policy. We also clarify misunderstandings about the use of hierarchical linear models for studying trajectories of crime. Our basic conclusion is that methods in criminology need to be more tightly linked with theory.