Comparing different Information Visualization (InfoVis) techniques is a challenging task and a necessary step to reach the users and their tasks. We evaluated the effectiveness in visualizing psychotherapeutic data of two InfoVis techniques, namely the Stardinates and the Parallel Coordinates by a comparative study with 22 participants. Based on three research questions we interpret the results of our study in order to derive statements on both visualization techniques. We evaluated (1) the time participants were engaged in testing our material, (2) the number of correct answers, (3) subjects? statements, which were categorized by the type of statement, and (4) the subjects? key statements in comparison to those defined by an expert. Our empirical results indicate that the Stardinates are a more appropriate method for interpreting such highly structured data in detail whereas Parallel Coordinates show advantages for gaining information at the first glance.