Abstract: A device for model-based diagnosis of a technical system, wherein the device determines which parameter is to be measured as the next one, and derives further parameter values from values for specific parameters. For these values, a process often referred to as the “propagation of values” employs a library with models of the component types and a model for the design of the technical system. The purpose of its device is to efficiently store information about measures with which parameters values are determined, and to quickly evaluate the determined values. This information establishes under which prerequisites measures may be implemented, and what their implementation costs. One aspect of the invention establishes that and how this information is stored in libraries of component types so as to be re-used. The primary advantage: the cost of producing the diagnosis device is reduced significantly in comparison to the state of the technology.