The information is already in the room

The most common explanation for a bad decision is that the team lacked information. It is usually wrong. In most rooms the information was present, held by someone who did not say it, or said it once and moved on.

The experiment that shows it

Stasser and Titus built a deliberately unfair task. They gave a group a decision to make, and split the relevant facts so that no individual held enough to identify the best option, but the group collectively did. All the group had to do was pool what it knew.

Groups reliably failed. They spent their discussion on the facts several members already shared, and under-discussed the facts held by only one person, which were precisely the ones that would have changed the answer.

Stasser, G., & Titus, W. (1985). Pooling of unshared information in group decision making. Journal of Personality and Social Psychology, 48(6), 1467-1478.

The effect has its own name, the hidden profile, and decades of replication behind it. A meta-analysis of information sharing and team performance found the same pattern at scale: teams share common information far more readily than unique information, and performance suffers for it.

Mesmer-Magnus, J. R., & DeChurch, L. A. (2009). Information sharing and team performance: A meta-analysis. Journal of Applied Psychology, 94(2), 535-546.

Why more data does not fix it

If the problem were a shortage of information, more analysis would solve it. But the shortage is not in the organization, it is in the conversation. Adding a report to a meeting that already fails to surface what one person knows produces a longer meeting with the same blind spot.

Organizations do not usually fail because they lack information. They fail because the information never reaches the decision.

What actually changes the outcome

Structure. Not more discussion, and not more consensus. Research comparing decision approaches found that structured conflict methods, dialectical inquiry and devil's advocacy, produced higher quality decisions than consensus-seeking, which produced happier groups that decided worse.

Schweiger, D. M., Sandberg, W. R., & Ragan, J. W. (1986). Group approaches for improving strategic decision making. Academy of Management Journal, 29(1), 51-71.

Whether people volunteer what they know is also not a matter of character. It is a property of the team: psychological safety predicts whether concerns, questions and errors are raised at all.

Edmondson, A. (1999). Psychological safety and learning behavior in work teams. Administrative Science Quarterly, 44(2), 350-383.

The practical version

Before the next significant decision, ask each person separately what they know that they have not said in the room, and why. The second half of that question is the useful one. If the answer is that it did not seem relevant, you have an agenda problem. If it is that it did not seem welcome, you have a different problem, and it is the more expensive one.