Methods for the evaluation of an interactive InfoVis tool supporting exploratory reasoning processes

Developing Information Visualization (InfoVis) techniques for complex knowledge domains makes it necessary to apply alternative methods of evaluation. In the evaluation of Gravi++ we used several methods and studied different user groups. We developed a reporting system yielding data about the insights the subjects gained during the exploration. It provides complex information about subjects' reasoning processes. Log files are valuable for time-dependent analysis of cognitive strategies. Focus groups provide a different view on the process of gaining insights. We assume that our experiences with all these methods can also be applied in similar evaluation studies on InfoVis techniques for complex data.