A new meta-analysis (pdf) of 72 studies, involving 4,795 groups and over 17,000 individuals has shown that groups tend to spend most of their time discussing the information shared by members,
which is therefore redundant, rather than discussing information known
only to one or a minority of members. This is important because those
groups that do share unique information tend to make better decisions.
Another important factor is how much group members talk to each other. Ironically, Jessica Mesmer-Magnus and Leslie DeChurch found that groups that talked more tended to share less unique information.
Hey, Alex, demand curves slope downwards! Hey Robin, people signal! Hey, Bryan, etc.