In 1957, British naval historian and management satirist Northcote Parkinson painted a cynical picture of a typical committee: It starts with four or five members, quickly grows to nine or ten, and, once it balloons to 20 and beyond, meetings become an utter waste of time – and all the important work is done before and after meetings by four or five most influential members.
As Parkinson would have it, numerous studies now confirm that, when it comes to teams, many hands do not make light work. After devoting nearly 50 years to studying team performance, the late Harvard researcher J. Richard Hackman concluded that four to six members is the team best size for most tasks, that no work team should have more than 10 members, and that performance problems and interpersonal friction increase “exponentially as team size increases.”
These troubles arise because larger teams place often overwhelming “cognitive load” on individual members. Most of us are able to mesh your efforts with and maintain good personal relationships with, say, three or four teammates. But as a group expands further, each member devotes more time to coordination chores (and less time to actually doing the work), more hand-offs between the growing cast of members are required (creating opportunities for miscommunication and mistakes), and because each member must divide his or her attention among a longer list of colleagues, the team’s social glue weakens (and destructive conflict soars). Following my earlier LinkedIn piece, findings about group size are reminiscent of psychologist George Miller’s famous conclusion that seven was a “magical number” because people could only hold “seven, plus or minus two” numbers in short-term memory. Both Hackman and Miller found that, once people start trying to deal with double digits, the cognitive overload takes a toll.
These findings help explain why the average restaurant reservation in the United States is for a party of four. Think of the last time you were at a dinner with a group of 10 or 15 people. It is difficult, perhaps downright impossible, to have a coherent and emotionally satisfying conversation that engages each member of the party all at once. Typically, the group breaks into a series of smaller conversations or a few people do all the talking and the others say little or nothing.
Some organizations learn about the drawbacks of oversized groups the hard way. Retired Marine Captain and former U.S. Senator James H. Webb explained why the “fire team” – the basic combat fighting unit – shrunk from 12 to 4 during War II. Webb wrote in the Marine Corp Gazette that this “12 man mob” was “immensely