The Common Knowledge Effect on Teams

A great deal of work today is accomplished within and by groups. Often a diversity of experience and knowledge is sought for problem-solving teams, with the intent of capitalizing on the diverse base of expertise represented by the team's members.  We certainly know that group outcomes can benefit from diverse perspectives and expertise, however it is well documented that groups typically fail to capitalize fully on the intellectual assets of its members.

One of the primary problems faced by most teams is what is referred to as the Common Knowledge Effect.  This effect, which has been heavily researched, shows that information that is known by all team members, prior to their discussion, has a more powerful influence on decisions than information that is not previously known by all.

It turns out that relevant information known to (shared by) only a few of the group members is either not introduced to the group at all, or is overlooked when it is shared.  Instead, groups tend to mention and discuss information that is common to and known by all the group members.  Typically, this is because...

• Shared information is socially validating for the members; they know that the information will be accepted by the group.
• Most group member's preferences are supported by shared information. Given that they are more inclined to offer information that supports their preferences, they speak about shared information more.
• People are resistant to changing their initial choices or existing judgments.
• We tend to mistake shared information for critical information, over-weighting its value and importance.

The impact of the common knowledge effect is to therefore eliminate the advantages sought by creating a team of diverse perspectives.  Instead, the group comes together and bases their decisions on information that they all possessed and understood prior.  Any single member would have likely forged as good a decision on their own, as did the group working together.  

For a team to truly be a success they must learn to harness the strengths of all of its members, finding ways to capitalize on the unique knowledge and experiences of each.  This requires the group to recognise the potential impact of the Common Knowledge Effect and to find ways to circumvent it from limiting their insights and options.  

To avoid making false assumptions by basing the decision primarily on shared information, teams should consider...

• Ensuring that all team members get airtime within which to share their expertise
• Ensuring that all information is heard and respected; no information is to be discounted
• If you have members that are reluctant to share their thoughts vocally, consider having all members share relevant information in writing, or conduct a written brainstorming session at the onset of the meeting, prior to discussing the issue.
• Establishing a clear understanding of the strengths of each team member, placing value upon such diversity.
• Emphasizing open inquiry, questioning fully all information brought to the table.

As with most things, understanding that the Common Knowledge Effect is a possibility is the first step to overcoming its biases and influence.  However, you need also be vigilant in guarding against its effects, working to ensure that the expertise of all team members contributes to the decisions and success of the team.