Spatial decision support systems: An overview of technology and a test of efficacy

A laboratory experiment was used to investigate the effects on deciision-maker performance of using geographic information system (GIS) technology as a spatial decision support sysllem (SDSS). GIS are increasingly being used for decision-making, yet research about their contributions to the performance of decision-makers has been lacking. This study makes a contribution to that apparent void. Volunteer subjects completed a site location task that required decisions to be made based upon spatially referenced information. Performance was operationalized as elapsed time and accuracy. The task environment was manipulated in two dimensions. In one dimension, task complexity was varied on two levels. In the other dimension, some subjects were provided a geographic information system as a decision aid; the rest were not. Significant differences were found between task solutions developed by SDSS users and those developed by non-SDSS users. SDSS users experienced shorter solution times and fewer errors for both levels of task compl~xity. The study builds upon and extends image theory as a basis for explaining efficiency differences resulting from different graphical displays of spatial information.