In the past few years, multimodal interaction is gaining importance in virtual environments. Although multimodality makes interaction with the environment more intuitive and natural for the user, the development cycle of such an environment is often a long and expensive process. In our overall field of research, we investigate how model-based design can help shorten this process by designing the application with the use of high-level diagrams. In this scope, we developed ‘NiMMiT’, a graphical notation especially suitable for expressing multimodal user interaction. We have already experienced the benefits of NiMMiT in several in-house applications, and are currently assessing the value of NiMMiT with respect to existing notations. In this paper we report on our comparison of NiMMiT against some well known data-driven modeling notations.