A hierarchical linear model was employed to simultaneously examine the influence and relationships of individual-level and group-level variables on Group Support System (GSS) usage and performance. The analysis revealed that when the level of consensus among group members (COA) was low, perceived usefulness and ease of use served as critical factors in GSS usage; however, when consensus among group members was high, the influence of usefulness and ease of use diminished. The degree to which users utilized the system as intended by the designers (faithfulness of appropriation, FOA) had a positive effect on individual-level performance but did not moderate the effect of individual GSS usage on performance. That is, while using the system as intended by designers is important, GSS usage was found to have an absolutely significant positive effect on improving individual work performance.