A group usually produces a better decision than its average member and a worse one than its best.
Which of those two outcomes appears depends almost entirely on .
Unstructured discussion reliably on what the first confident speaker proposed.
Information held by only one person is the least likely to be raised and the most likely to matter.
Groups discuss what everybody already knows, because shared facts receive more and more agreement.
Two s correct most of this at a cost of a few minutes.
Writing an individual judgement before any discussion preserves the independence of each estimate.
Asking the most junior person first removes the that a senior opinion would otherwise set.
Both are well evidenced and both are abandoned under time pressure, which is when they matter most.
is the variable that predicts decision quality better than expertise does.
A group with one member willing to state an objection outperforms a more expert group without one.
Assigning that role formally works less well than protecting the person who takes it naturally.
An assigned objection is by everybody in the room, including the person making it.
Meeting size has a that most organisations exceed without noticing.
Above about seven people, the number who speak stops rising and the number who agree in silence begins to.