The invention relates to a diagnosis method which permits continuous monitoring of the available resources in a production process, into which a number of supply links are incorporated in the form of a network and supply a system provider or other supply links with raw materials, semifinished products, components and services. Each supply link has an input buffer, an output buffer and a process stage, on the basis of the design of which the supply link determines an identification number which characterizes the operating state of this supply link. The predicted demands of the system provider and the current reserves in the buffers of each supply link are used as a basis to calculate—using the identification numbers of the supply links—for each supply link whether its reserves satisfy the predicted demands of the system provider, i.e. whether it is capable of supplying. Deficits in the stocks of a supply link are notified to all the other supply links, so that a high transparency of the current state of the resources in the supply network is achieved without the supply links having to disclose internal matters concerning their processes. The method is suitable in particular for monitoring resources in supply networks into which supply links outside the company are incorporated. This is a decisive difference in comparison with the PPC systems available on market, which do not take into account suppliers and subcontracted suppliers outside the company.