Do birth dates affect performance?

Are the best cricketers of our times born with talent or have they been unwittingly dealt the best hands in life, courtesy of their lucky birth date? Millions of people around the world believe in astrology and auspicious dates but could it be much simpler than that? How many potentially great cricketers were never heard of, lost to the game before their talent was allowed to blossom?

In his best-selling book Outliers, Malcolm Gladwell explores the playing rosters of many American and European team sports (ice hockey, basketball, football) and discovers the amazing coincidence of birth dates. In a system that has a junior selection system based on a calendar year (January 1 to December 31), his statistics show that an extraordinarily high percentage of athletes’ birthdays are from the first few months of the year.

His theory is that in junior sport these boys naturally tend to be bigger, stronger and physically more advanced than boys who are born later in that year. At a young age, this is a significant advantage and leads to the same group of boys dominating their junior teams, being regularly selected for the top teams, getting the best coaching and widening the gap between those born later in that 12-month cycle.

His is a convincing argument which also suggests that the younger kids get discouraged by that disparity in physical maturity (and not getting selected for junior rep teams) and they tend to drop out of that sport, thereby fulfilling the prophecy of the older boys who continue to make all the top teams through to adulthood.

It made me wonder if cricket has a similar story to tell. Do the best international cricketers owe something to their birth dates and the natural advantage it gave them at a young age? Does physical maturity and size matter for a non-contact sport like cricket? After all, most of the best batsmen are relatively small fellows (Brian Lara, Sachin Tendulkar, Don Bradman, Allan Border, Ricky Ponting, Sunil Gavaskar etc).

In order to test this theory in a very non-scientific way, I decided to look at the current World Twenty20 squads of every major cricketing country and see how many of the 15 squad members were born in the first or second half of the year. Here are the results:

Oh well, there goes that theory I thought. Most countries, England apart, are inconclusive or lean strongly towards the reverse of Gladwell’s theory. No advantage in being born earlier in the calendar year.

It then occurred to me that most countries, England apart, have cricket seasons that mirror the Southern Hemisphere summer. At junior levels, do they select age-group squads from a July or September cut-off date? If so, does that go some way towards explaining the bias in countries like Australia, NZ, Pakistan and India towards boys born in the second half of the year? India especially has an amazingly high ratio, 14/15 of their current T20 squad born between July and December.

Now I’m the first one to admit that looking at a single Twenty20 tournament only tells a tiny fraction of cricket’s long history. And I’m not even sure if these countries do indeed have junior cut-offs that runs from say September 1 to August 30 for example. I’d be fascinated to hear from people around the world who may be able to shed some light on this question. Perhaps there’s more to this theory after all!

And if England’s junior age cut-off operates according to a calendar year, that makes it even more interesting…..are we on to something here? Their stats show a leaning towards players born in the first six months.

Going back in time, let’s look at the World Cup winning teams and runners-up (if it involves Australia, New Zealand, England or the subcontinent) from 1983 to 1992. This safely eliminates anybody currently playing in the World Twenty20. I’ve looked at New Zealand’s semi-final team from 1992 too.

The pattern still seems to be (largely) holding true. England’s statistics from that period are slightly misleading because so many of their players from that era were not born in England and may have started their junior careers under some other country’s system (Gladstone Small, Graeme Hick, Allan Lamb, Chris Lewis, Philip DeFreitas and many more). If you take out those ‘foreign born’ players, the figures support this theory even more.

Confining my analysis to these four countries (India, Pakistan, Australia and England), I had a quick look at the top 10 players in the current ICC rankings for Tests and ODI’s. For players from these nations, batsmen and bowlers, the trend is still consistent:

Even if the cut-off dates do not support my theory, it is quite odd that all countries that play cricket between September-March seem to have more cricketers born in the second half of the year. Why is that? Unless there's some unusual factor in play, the results should be roughly 50/50 but India especially has nowhere near a 50% ratio. It's massively skewed in favour of players born in the second half of the year. What's the reason?

Another interesting fact is that when a player defies the broad trend for his country, it is usually a child protege, someone who was always destined to make it. These are the rare talents who were always likely to be much better than their age cohorts. It didn’t really matter if they were competing with older boys. Shahid Afridi, Michael Clarke, Tendulkar, Hasan Raza and Vinod Kambli for example are all born in the first half of the year (opposite to the trend). Their genius (at a young age) was never going to be denied by anything, least of all a favourable birth date.

Gladwell’s examples aren’t just restricted to sport. He cites numerous research studies in mathematics, science, reading and university education where the statistics are significantly skewed in favour of the oldest children of that year batch. It’s a natural advantage that seemingly begins at a young age and keeps repeating itself over a person’s lifetime as they continue to benefit from the common mistake of comparing maturity with ability at too young an age. There is no doubt that in most aspects of life, a child is advantaged by being the oldest in his/her age group and if this means they keep getting selected in the ‘gifted’ stream or team, their improvement continues with the best coaching, encouragement and opportunities. Their inevitable success is almost a fait accompli.

If this phenomenon is actually true in cricket, the long-term answer might be in having a rolling cut-off date for junior cricketers. It might be Jan 1 followed by July 1 the next year and so on. Theoretically, this should give all youngsters a fair chance to compete with boys of their own size and maturity. It could mean that we have twice as many talented kids to choose from once that maturity/size factor evens out.

For Australia and New Zealand with small populations where cricket competes with other sports for the best athletes, this may be a crucial tool in talent retention. For India with a billion-plus people to whom cricket is clearly the number one sport, perhaps it doesn’t really matter. From what I’ve seen on the maidans and alleyways in India, a shortage of talent is never going to be a problem in that part of the world!