The starting point of the research project was the hypothesis that the "principle of proportionality", which is fundamental to law, is related to the "economic principle". The resulting methodological similarities were intended to enable a cross-disciplinary bridge to be built, which would allow the findings of economic analysis to be made fruitful for legal issues. This was practically tested in three study areas in order to be able to better classify the performance of the analytical tools. The foundations for interdisciplinary bridge building are found in the rational-choice paradigm. In both disciplines, this paradigm calls for an examination of the relationship between the purpose-means-relations: among the design options under consideration, the one must be selected that is expected to be as (freedom- or resource-) sparing as possible, in other words, the most "waste-free" solution to the control problem.The results of the economic analysis can thus be "translated" in such a way that, within the framework of "necessity", they support the search for control instruments that are equivalent to the objective but less disruptive. supports. The core of the positive economic analysis is the motivational situation of those actors whose behavior is to be influenced by a changed legal framework. In this context, the classical behavioral model of economics proved to be too limited. It therefore had to be developed further in line with the findings of research in institutional economics into homo oeconomicus institutionalis. This behavioral model takes into account not only the consequentialist, strictly situational utility orientation of the model person, but also other factors influencing behavior, including above all those that are institutionally mediated. If one takes the motivational situation of the actors as the starting point for policy-advising design recommendations, it becomes apparent that an understanding of governance dominated by imperative behavioral specifications leads to less favorable results, both in terms of the degree to which goals are achieved and in terms of the freedom-impairing effects, than a mixed-instrument approach oriented toward the model of "responsive regulation." According to this model, the law can no longer simply assume that those subject to the law will "obediently" execute the legal commands. It must ask itself what other factors determine behavior and under what boundary conditions changes can be expected in the direction of the desired behavior. For this reason, too, it must engage with the cognitive program of the behavioral sciences. This linkage opens up new perspectives for interdisciplinary research on the consequences of laws.