a common representation. Additional information such as domain- or application-specific constraints may also be encoded to provide a rich representation. The coordination model is based on generic information such as language grammars and constraints as well as application-specific information such as concrete models and application-specific constraints. This means that even though the same languages are used across several products, each product has a specification of its own unique coordination model. The coordination model is used as basis for various forms of reasoning in the final step of the method: the application step. Step 3: application The goal of the application step is to take advantage of the coordination model. The coordination model allows tools to derive three layers of useful information. First, the coordination model can be used to enforce consistency across multiple languages. The coordination model specifies consistency relations such as how elements from different languages can refer to each other. Tools can enforce referential integrity and perform static checks of the final system before deployment. Second, the consistency relations are used to navigate, visualize and map the web of different languages in a development setup. This information is used to quickly link and relate elements from different languages and to provide traceability among different models. Third, based on consistency relations and navigational information about how elements are related, tools can provide guidance, specifically completion or assistance. Model completion can for instance be provided in a generic manner across domain-specific tools. Evaluation of the coordination method The coordination method can best be seen as a conceptual framework that prescribes a certain workflow when working with multiple languages. The three successive steps that constitute this workflow are not supported by an integrated workbench or development environment. The focus is rather on extending the developer's existing environments to add support for (1) identification, (2) specification, and (3) application. The main advantage of this approach has been that developers have actually tested our work and given us feedback. This kind of evaluation of the method is valuable because it reduces the risk of solving a purely hypothetical problem. Several papers introduce the different steps of the coordination method, report on this evaluation, and elaborates on the technical aspects of each individual experiment. Overall, the results have been promising: a significant number of errors have been found in production systems and given rise to a constructive dialog with developers on future tool requirements.