The Vienna Development Method (VDM) is one of the longest established
model‐oriented formal methods
for the development of computer‐based systems and software. It consists of a group of mathematically well‐founded languages and tools for expressing and analyzing system models during early design stages, before expensive implementation commitments are made. The construction and analysis of the model help to identify areas of incompleteness or ambiguity in informal system specifications, and to provide some level of confidence that a valid implementation will have key properties, especially those of safety or security. VDM has a strong record of industrial application, in many cases by practitioners who are not specialists in the underlying formalism or logic. Experience with the method suggests that the effort expended on formal modeling and analysis can be recovered in reduced rework costs that develop from design errors.