Abstract: The present invention is directed to a method and a system for computer-based visual data evaluation which allows on-the-fly viewing, evaluation and querying of complex databases with simple user operations. A visual chart representation of the data set is used to select for display data subsets through interaction between the user and the system within the chart of the data set. The results of the user's data subset selections are displayed in the chart. A chart of only the data subset may then be selected and displayed through interaction between the user and the system within the displayed data subset. The steps of selecting and displaying the results of data subset selections may be continued in an iterative visual data evaluation process. A record of the user selected data subsets is maintained, including a textual record of the data subset and distinct visual symbols for each of the data subsets created.