When you’ve got a small group, you don’t need to constantly formalize things. You communicate and you know what’s going on. If you have a question about something, you ask someone. Formalized rules, deadlines, and documents start to seem silly. Everyone’s already on the same page anyway.

Ten-groups
According to British author Antony Jay, there are centuries of evidence to support the idea that small groups are the most efficient. In “The Corporation Man,” he talks about how humans have worked in small groups, usually five to fifteen people, as hunters and farmers for hundreds of generations. The ideal group size is a ten-group:

He found the most efficient to be organised in groups of eight to fourteen people which he came to call ‘ten-groups’, each group free to find its own way towards a target set for it within the general objects of the corporation…

“The basic unit is [a group] which varies from three to twelve or fifteen in number, and perhaps optimizes somewhere around ten; that this group is bound together by a common objective, and that the bond of trust and loyalty thus formed can become an extremely powerful uniting force; that the group needs to decide on (or at least take part in deciding on) its own objective, and to work out for itself how that objective shall be achieved…”

He offers up interesting examples to back up the theory, from sports teams to juries to army squads:

Jay draws attention to units of around this size in many fields beyond the corporation. A committee works best with about ten members; if it grows much beyond that size the extra people do not take a fully active part. Nearly all team games use a group of about ten on each side. Juries have 12 members and the Jewish minyan 10. In an army, organization often decides life and death, and under this pressure armies, too, adopt a basic unit of about ten; the British army, the US army, the ancient Roman army and that of Genghiz Khan, in fact every long-standing successful army, has built up its larger formations from squads or sections of about this size.

That mention of the Roman army takes us back some two thousand years, and Jay traces the ten-group back still farther, back to the foraging communities. The ten-group, found today as a structural unit in successful corporations began, he argues, as the male hunting-group of pre-agricultural times, still with us and still functional.

Groups this size succeed because they have mutual dependence and a common objective:

This group displays qualities in addition to its size. Small enough for the contribution of each member to make a noticeable contribution, in order to function it needs mutual dependence, a common objective and a single criterion of success for them all; as the hunting band fed or went hungry together so members of the modern ten-group must receive praise, blame and material rewards collectively for the unit to function at its best.

Two-pizza teams
The tech world equivalent of ten-groups: two-pizza teams. Here’s what Marc Hedlund says about two-pizza teams:

I believe both Apple and Amazon (two companies I respect a lot for their version 1.0s) talk about “two-pizza teams” — that is, keeping the team small enough that it can be fed with two pizzas…If the company that made the iPod believes in a two-pizza team, how can you justify putting 90 people in the room?

Bottom line
If you’re working in a group bigger than 15 people, you’re fighting human nature. Start a satellite group and see if you can lose the busywork and bureaucracy that inevitably accompany oversized teams.

Related
Some other Antony Jay quotes:

He’s suffering from Politicians’ Logic. Something must be done, this is something, therefore we must do it.

‘Referring the matter to a committee’ can be a device for diluting authority, diffusing responsibility and delaying decisions.

The uncreative mind can spot wrong answers, but it takes a very creative mind to spot wrong questions.

You can judge a leader by the size of the problem he tackles. Other people can cope with the waves, it’s his job to watch the tide.

You can stop focusing on extraneous collateral and pay attention to what matters instead.