It’s the other Parkinson’s: the progressive degeneration of
a committee’s ability to make decisions as the committee adds more members.
English historian Cyril Northcote Parkinson observed in the
1950s that decision making is severely impaired in committees of more than 20
people. Now physicists have shown that the size of a country’s executive
cabinet appears to be linked to that country’s overall efficiency, and they
have found a possible mathematical explanation.
Stefan Thurner, a physicist at the Medical University of
Vienna, and his collaborators looked at the overall efficiency of virtually
every government on the globe, as measured by United Nations and World Bank
indicators taking into account factors such as literacy, life expectancy and
wealth.
The researchers then looked at each country’s executive
cabinet. “Cabinets are a good representation of countries,” Thurner says.
Common sense would suggest that smaller cabinets would find it easier to reach
a consensus. But to get the rest of the country behind a decision, cabinets
also have to be large enough to represent of a wide range of constituencies,
Thurner says. “Behind every minister there is a set of lobbyists, interest
groups and a large bureaucracy.”
On average, the team found, a country’s development was tied
to the size of its executive cabinet. For example, Iceland, which the United
Nations ranks as the world’s most developed country, has a cabinet of just 12
members; the United States, which ranks 12th, has 17 cabinet members; Myanmar
and the Ivory Coast, with 35-strong cabinets, rank 132nd and 166th.
The researchers also tried to figure out exactly how a
committee’s size affects its efficiency and to explain Parkinson’s 20-person
rule.
The team simulated committees as networks in which each
member was a node. Before a vote, each member’s opinion could be influenced by
those of its immediate neighbors in the network; adjacent nodes could
represent, for example, ministers belonging to the same political party. The
simulation found that committees of 10 members or less could almost always
reach a consensus (with one mysterious exception for the number 8). For larger
committees, the chances of getting to a consensus were lower, and the chances
decreased even more rapidly for committees of 20 or more. The results show that
Parkinson’s law is not an accident, but “a robust consequence of the
opinion-formation model,” Thurner says.
“It’s interesting that they find a correlation,” says Yaneer
Bar-Yam of the New England Complex Systems Institute in Cambridge, Mass. However, Bar-Yam points out
that the correlation is only true on average. In fact, the data show some
important exceptions. For example, Australia,
Canada and New Zealand have large cabinets but
high efficiency scores. A committee’s effectiveness, Bar-Yam says, strongly
depends on how the committee is organized. “One of the great examples today is
Wikipedia,” he says. The online encyclopedia manages to function despite being written
and edited by thousands of volunteers because of the way it’s structured, he
says.
Found in: Science & Society