The article discusses problems that arise from comparing different kinds of presentation modes such as texts, pictures or animations with regard to learning outcome. These comparisons are confounded with or depend on other variables like quality of the instructional design, learning content, familiarity with the presentation mode as well as learners' willingness to invest mental effort. Other variables concern the implicit stimulative nature to make a prediction, interactivity possibilities, the fit between the type of information presentation and information retrieval, the level of delivery media (e.g., books or computers), the level of sensory modalities and the fixation of learning time. Due to these problems, comparing different kinds of presentation modes seems to be an inappropriate research approach and will not lead to general conclusions. Instead, other research approaches are presented and critically discussed like elaborating, extending or contrasting theories of multimedia learning, testing design principles or investigating moderator variables.