There is a persistent belief that more voices produce better decisions.
Irving Janis documented the opposite in his research on groupthink, and subsequent decades of organisational psychology have only reinforced his findings. Groups systematically suppress dissent, overweight shared information, and converge toward the position held by the most senior or most vocal person in the room — not the most accurate one.
The illusion of distributed wisdom
When a team reaches consensus quickly, it usually means one of three things: the decision was trivial, someone dominant steered it, or members self-censored to avoid conflict. None of those are good signs. Genuine disagreement, worked through carefully, produces better outputs than smooth agreement.
A study across 120 management teams found that teams reporting high levels of interpersonal harmony made significantly more errors on complex analytical tasks than teams with structured conflict processes. Harmony felt better. It performed worse.
What to do instead
Assign a formal dissenter before any significant decision meeting. Not a devil's advocate who performs skepticism — an actual person whose job is to find the strongest case against the preferred option. Pre-mortems work similarly: before committing, ask the group to assume the decision failed and explain why.
Consensus should be a red flag, not a green light. If everyone agrees immediately, you probably did not examine the decision hard enough.