This research tested the effects of an expert on strength of consensus and decision quality when the expert is a member of a consensus group. The purpose of this research is to help managers effectively use experts to increase decision quality without reducing consensus. If the expert gives the group relevant information, decision quality should increase. If group members believe the expert’s information is accurate, they'll perceive their decision is high in quality. If the group members perceive the decision is high in quality and perceive they had an opportunity to express their views, strength of consensus should be high. Subjects (110 total) in this experiment were placed in 22 groups of 5. Eleven experimental groups had one expert; 11 control groups had no expert. Experts were selected from a pool of astronomy students. The experts’ level of expertise was assessed by their score on a pre-test and score on the Lost on the Moon exercise. I measured the first dependent variable, strength of consensus, with a post-task questionnaire and two statistical measures of the closeness of rankings. I measured the second dependent variable, decision quality, by the closeness of the group’s ranking to the ranking developed by NASA experts. I measured perceptions of opportunity to express views and perceptions of decision quality with a post-task questionnaire. I also measured group members’ use of expert power and leadership emergence with a post-task questionnaire. Experts had no effect on decision quality, largely because the expert manipulation was unsuccessful. Perceptions of decision quality were correlated with strength of consensus. Perceptions of the opportunity to express views were only marginally correlated with consensus. Finally, experts tended to emerge as leaders. I concluded that experts will increase decision quality unless they give the group the wrong information or no information. I also concluded that experts won’t hurt consensus unless they dominate the group discussion. Perceptions of decision quality and perceptions of the opportunity to express views are important variables for achieving consensus. / Master of Science