OSCIS03The use of Group Support Systems has been researched repeatedly using many task-type. For brainstorming tasks the process support of the system have been restricted to ensuring member anonymity and allowing the simultaneous entry of ideas. Little work has been done investigating other process improvements for idea-generating groups. In this paper, we investigate the effect on idea quality and quantity of decomposing a brainstorming task with a South African setting. Using Team Expert Choice, an Analytic Hierarchy Process (AHP) based group support system. We conduct an experiment with two groups. We hypothesize that task decomposition will generate more and better quality ideas. Our findings show that task decomposition resulted in 40% more ideas than no decomposition; the effect on decision quality is statistically significant only when decision quality is measured as the number of good ideas.