A review reports that relative-age effects tied to cohort cutoff dates bias selection into elite youth soccer and hockey¶

Claim · All claims
Evidence · 1 study · review r2 · q2
Currency · newest study 2005 · not yet checked against its sources · not reviewed by a person
Evidence quality · No study behind this claim is a peer-reviewed article with a DOI: it rests on a source with no registered publication record (a web page, book or unpublished report). It is kept because 2 design pages cite it; treat it as a lead to check, not an established finding.

Subclaims¶

q2 i? Professional soccer and hockey players are born 3–6 times more frequently in some months, and shifting cohort cutoff dates shifted which birth months were selected. → Ericsson 2005

Evidence¶

Ericsson 2005¶

Ericsson, K. A., Nandagopal, K., & Roring, R. W. (2005). Giftedness viewed from the expert-performance perspective. Journal for the Education of the Gifted, 28(3/4). https://eric.ed.gov/?id=EJ746057

q2 · i? · review · r2

Natural-experiment analysis by Helsen, Starkes, and van Winckel (2000) as reported here: Belgium changed its soccer age-cohort cutoff from August–July to January–December in 1997, and "children born in January to March immediately became the most highly selected."

"Within a single year, children born in January to March immediately became the most highly selected among the young soccer players."

Discussion¶

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