Glossary
Shared Information Bias
What is shared information bias?
Shared information bias, also called common information bias, is the tendency for groups to discuss information several members already know more than information held by only one or a few members.
How it is studied
Lu, Yuan, and McLeod combined 65 hidden-profile studies involving 3,189 groups. In these tasks, members need to pool their different pieces of information to discover the best option.
Groups discussed more common than unique information. Groups that covered more of the available unique information also made better decisions.
A hypothetical hidden profile
Three colleagues must choose the cheaper of two otherwise equivalent suppliers. Everyone sees Supplier A’s quoted price of $8,000 and Supplier B’s all-inclusive price of $10,000. Each initially favors A. But one colleague knows A requires a $900 setup charge, another knows it requires an $800 license, and the third knows it requires $700 in delivery charges. Each person’s private information alone leaves A cheaper.
Pooling all three additional charges reveals that A costs $10,400, making B the cheaper option under the stated criterion. A discussion focused on the shared $8,000 quote can miss that conclusion. This invented example illustrates the information structure of a hidden profile; it is not a result reported in the meta-analysis.
Why it matters
A meeting can cover familiar ground while missing the evidence that would change the decision. Asking members to bring forward information others lack is a reasonable response.
Before a decision, ask what each person knows that others do not and whether the discussion gives them a chance to explain it. A room full of agreement does not tell you that all relevant evidence has been shared.
The task design matters: hidden-profile studies deliberately make information sharing necessary.