1. A method of supporting a multistage decision process for computer-aided production of a work plan for a production process used to implement technical features on a workpiece, the method comprising the acts of: automatically classifying each desired feature to be implemented on the workpiece with reference to defined properties; selecting from a relational case database reference cases having properties similar to the desired feature in accordance with a previously defined similarity measure; automatically evaluating the reference cases in accordance with the similarity measure in presenting to a user the reference cases for selection together with production operations connected in a respective reference case to a production of the desired feature; deciding upon one of the proposed reference cases or interactively storing a new precedent as a new reference case; in relation to each production operation, automatically running through a hierarchical decision tree in accordance with decisions made by the user in which, starting from production operations associated with this selection, suitable cases being selected from the relational case database at each decision stage of the decision tree, said suitable cases being evaluated in accordance with the similarity measure corresponding to the relevant individual decision presented to the user; and storing each individual decision made by the user in the relational case database.