Children born just after a selection cut-off are heavily over-represented in elite squads, because early physical maturity is mistaken for talent.
The Canadian junior hockey study found birth months clustered immediately after the January cut-off. The mechanism is compounding rather than physical: the older child in the age band is selected, receives better coaching and more play, and the initial advantage of a few months' growth becomes a real one. The same skew appears in football, cricket and schooling.
In practice
- A squad list whose birthdays cluster in one quarter has told you about its selection process, not its talent pool.
- A school setting pupils by attainment at seven has partly sorted them by month of birth.
- Further reading
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- Subject
- Sport & Performance
- Essay
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