Increasingly sophisticated technologies, such as On-Line Analytical Processing (OLAP) and Geospatial Information Systems (GIS), are being leveraged for conducting community health assessments (CHA). Little is known about the usability of OLAP and GIS interfaces with respect to CHA. We conducted an iterative usability evaluation of the Spatial OLAP Visualization and Analysis Tool (SOVAT), a software application that combines OLAP and GIS. A total of nine graduate students and six community health researchers were asked to think-aloud while completing five CHA questions using SOVAT. The sessions were analyzed after every three participants and changes to the interface were made based on the findings. Measures included elapsed time, answers provided, erroneous actions, and satisfaction. Traditional OLAP interface features were poorly understood by participants and combined OLAP-GIS features needed to be better emphasized. The results suggest that the changes made to the SOVAT interface resulted in increases in both usability and user satisfaction.