Outliers: The Story of Success · chapter 1 · id outliers-c1-07-canadas-hockey-age-cutoff-was-
“Canada's hockey age cutoff was moved from January 1 to different dates in various provinces (some to September), but the relative age effect simply shifted to favor players born just after the new cutoff date.”
VERIFIEDconfidence: high⚠ extracted by pipeline, re-audit pending
Receipts
Birth Advantages and Relative Age Effects editorial (2021), Frontiers in Psychologysource alive
When age cutoff dates are changed, the relative age effect shifts correspondingly, confirming the mechanism is the arbitrary cutoff rather than seasonal birth quality differences.
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