Effectiveness of decision support systems. development or reliance effect?

Despite the large number of empirical investigations of DSS on decision outcomes, very few studies have incorporated longitudinal designs to assess DSS effectiveness. This study proposes that effects of DSS on decision outcomes develop over time. The study evaluated whether improvements in decision quality typically associated with DSS were due primarily to 'development' or 'reliance' effects. Using an add-on and take-away design, we examined whether introduction of DSS contributes to decision quality after controlling for task familiarity. We also evaluated decision-makers' performance after removing the DSS. Results indicated that although DSS contributed to decision quality after controlling for task familiarity, increased decision performance of DSS-aided decision makers may be due to reliance rather than better conceptual understanding of the decision problem. Implications of these results for design and implementation of DSS are discussed. (C) 1997 Elsevier Science B.V.