Interactive installations engage people in different ways, many of which are different than originally intended by the designer. We present a model that illustrates the differences between the intended experience and the actual experience of people. The model is demonstrated through the analysis of one interactive installation at the Science Museum (London) and the various parameters are mapped and visualized. We suggest that the participants of interactive installations engage differently than originally intended by the designer, which can be defined here as “deviation”. There are several levels of deviation, and the proposed model will illustrate the critical interaction stages and visualize the deviations. This model offers new tools for designers and curators alike.