Decision Support Systems (DSS) should increase the effectiveness of a decision and the efficiency of the decision making process. The success of DSSs has varied among individual users. One explanation for this variation is that individual’s spatial ability has a moderating effect on performance. Another factor found to impact decision performance is the structure of the task.

The purpose of this study is to determine whether spatial ability factors have a moderating effect on decision making performance in a DSS environment under differing task structure. Three of the major factors of spatial ability (spatial scanning, spatial relations, and field independence) and two levels of task structure (moderately complex and complex) are considered in the study. Spatial scanning and field independence were assessed by the Kit Factor-Reference Cognitive Tests, Map Planning Test and Hidden Figures Test, respectively [Ekstrom et al., 1976]. Spatial relations was assessed by the Mental Rotations Test [Vanderberg & Kuse, 1978]. Model formulation and data analysis are two stages of decision making considered in the study. Decision making performance is assessed by time to complete the task, DSS features used, decision confidence, and decision accuracy. Computer experience is treated as a control variable.

Fifty Master level students in the School of Business attended three experimental sessions which involved completing several spatial ability tests, participating in a ninety minute lecture on the software package, and completing four practice problems and two experimental cases. The software package employed in the experiment is IFPS, a DSS generator.

The results of the study indicate that spatial relations has a moderating effect on decision confidence during the data analysis stage of decision making. Furthermore, there is a significant moderating interaction effect between spatial relations and task complexity when performance is assessed by decision confidence. Spatial relations is found to be more significantly related to performance in the complex case than in the moderately complex case.