Trying to make a big office decision in a meeting? Common sense suggests asking certain staffers to present pertinent facts to consider. But if you want groups to make a well-informed decision, make sure every member has the same knowledge coming to the table.

We're more likely to discuss an issue at length, says James Larson, Jr., Ph.D., if we're aware of all sides before the powwow begins. The psychology professor explains this as a simple matter of odds. If three people know about X, and only one knows about Y, there is simply more opportunity for X to get mentioned, he says.

Pooling information is vital to making sound decisions, especially the life-threatening choices made by doctors. Without all the facts in place, it's all too easy for a physician to prescribe a dangerous drug or deliver the wrong diagnosis to patients. Larson, of the University of Illinois at Chicago, and fellow psychologists asked three-person teams of medical students and interns to diagnose two hypothetical cases. Knowledge of some symptoms was shared among all team members, while only a few doctors knew other facts. The researchers found that subjects discussed shared information first and foremost-and the less subjects pooled information, the less accurate their diagnosis. After a period of discussion, group members begin to feel they have enough information to make a decision, he says. If that point comes before all the unshared information has been raised, there is a danger they will commit a decision-making error.

The person with the best chance of correcting a group's tendency to ignore new insights is the team leader. A leader can pay attention to unshared information and bring it back on the table, Larson says. That way, workers in all professions are sure to see all sides of a dilemma-leading to wiser, sounder decisions.