Intuitively, it would be acceptable that through examination of data and various verification procedures, a human being can eliminate erroneous input readings or calculations. This report is concerned with investigating this aspect through the use of interactive graphics. It is proposed to investigate this aspect through a case study in a competitive game situation. When taking sonar readings one can anticipate that periodically erratic readings will occur. Thus the data displayed may appear to be inconsistent when visually compared to other historical data. This report proposes a method for eliminating this erroneous data, and the submarine vs. task force game in the Moore School is the vehicle for investigation. Specific displayed information is made light sensitive. Then, by using the light pen, the player eliminates that information considered to be inconsistent. Thus, a more reliable estimate is created.