Accuracy isn't so clear when the problem could have alternative solutions, Sniezek said. In the study, the groups considered tasks that varied in the difficulty of demonstrating why a solution is a good one. Each individual was asked to report his or her confidence level in solving the problem at both the beginning and conclusion of the task. Groups were more effective than individuals in solving subjective tasks, such as definitively forecasting a result. In fact, large groups often displayed unrealistic overconfidence.
Confidence is an imperfect indicator of accuracy.
Don't let someone's certainty be a proxy for explanation. This may not always be possible. People should recognize that an individual's confidence can be influential above and beyond the reasons. In a report in May to the Midwest Psychological Association in Chicago, co-investigator Paul Zarnoth, a U. of I. doctoral student in psychology, said that a person with high confidence and strong arguments wields substantial influence. However, the study also found that if the highly confident person's arguments are not demonstrated convincingly, then the influence can be totally lost, Sniezek said.