delanceyplace.com 1/18/10 - birthdates

In today's excerpt - the effect of birthdate
on athletic performance:

"If you visit the locker room of a
world-class soccer
team early in the calendar year, you are more
likely to interrupt a
birthday celebration than if you arrive later
in the year. A recent tally of
the British national youth leagues, for
instance, shows that fully half of
the players were born between January and
March, with the other half
spread out over the nine remaining months.
On a similar German
team, 52 elite players were born between
January and March, with just
4 players born between October and December.

"Why such a severe birthdate bulge?
Most elite athletes begin playing their
sports when they are quite
young. Since youth sports are organized by
age, the leagues naturally
impose a cutoff birthdate. The youth soccer
leagues in Europe, like
many such leagues, use December 31 as the
cutoff date.

"Imagine now that you coach in a league for
seven-year-old boys and are assessing two
players. The first one (his name is Jan) was
born on
January 1, while the second one (his name is
Tomas) was born 364
days later, on December 31. So even though
they are both technically
seven-year-olds, Jan is a year older than
Tomas - which, at this tender
age, confers substantial advantages. Jan is
likely to be bigger, faster,
and more mature than Tomas.

"So while you may be seeing maturity rather
than raw ability, it
doesn't much matter if your goal is to pick
the best players for your
team. It probably isn't in a coach's interest
to play the scrawny younger
kid who, if he only had another year of
development, might be a star.

"And thus the cycle begins. Year after year,
the bigger boys like Jan
are selected, encouraged, and given feedback
and playing time, while
boys like Tomas eventually fall away. This
'relative-age effect,' as it has
come to be known, is so strong in many sports
that its advantages last
all the way through to the professional
ranks.

"K. Anders Ericsson, an enthusiastic,
bearded, and burly Swede, is the
ringleader of a merry band of relative-age
scholars scattered across the
globe. He is now a professor of psychology at
Florida State University,
where he uses empirical research to learn
what share of talent is 'natural'
and how the rest of it is acquired. His
conclusion: the trait we commonly
call 'raw talent' is vastly overrated. 'A
lot of people believe there are
some inherent limits they were born with,' he
says. 'But there is surprisingly little hard
evidence that anyone could attain any kind of
exceptional performance without spending a
lot of time perfecting it.' Or, put
another way, expert performers - whether in
soccer or piano playing,
surgery or computer programming - are nearly
always made, not born."

Steven D. Levitt & Stephen J. Dubner,
Superfreakonomics, William Morrow,
Copyright 2009 by Steven D. Levitt & Stephen
J. Dubner, pp. 59-61.