Over the years, Garold Stasser and his colleagues have demonstrated that many teams exhibit "shared information bias" - i.e. teams spend a great deal of time discussing information common to all team members, and they do not share, discuss, and integrate privately held information effectively. As a result, teams make poor decisions because they do not leverage the unique knowledge and expertise of some team members.
How can teams overcome the shared information bias? People have described a variety of strategies, many focusing on a climate of psychological safety as well as strong process facilitation by the leader. I would argue that one other techique can be very helpful. Team members should ask the following question as they engage in collective problem solving: What information or data do we WISH THAT WE HAD in trying to solve this problem? Think about that question for a moment. In most cases, team members focus on what they already know, rather than thinking about what information they wish they had in order to solve the problem. By asking, "what data do we wish that we had," teams might encourage members to come forward with critical information that they might not have already shared for a variety of reasons. In short, building a wish list might invite those who can help fulfill those wishes to come forward.