Dropped Out Before They Ever Competed: A Population-Wide Registry Analysis of Relative Age Effects in Norwegian Track and Field from Age 10 to 25
Year: 2026
Type: article
Study design: Observational Study
Abstract: Relative age effects (RAEs), the overrepresentation of children born early in the selection year among participants in age-graded sport, shape who enters organised youth sport and who remains in it. The dominant theoretical account locates the generation of RAEs in adolescent talent-selection cycles, predicting amplification through adolescence. If selection instead occurs before children enter organised sport, participation-level inequities would need to be addressed at the entry stage rather than at adolescent talent identification. I tested this prediction using population-wide registry data 2011–2026 from the Norwegian Athletics Federation (87 624 athletes; 1 395 788 performances; the entire competing cohort), comparing birth-quarter distributions across ages 10–25 against monthly birth counts from Statistics Norway. Logistic regression with sex $$\times$$ age interaction tested for adolescent amplification; Manski-style bounds quantified the influence of athletes appearing briefly without a recorded birth date (61% at ages 10–12; overwhelmingly short-career early leavers). At age 10, the youngest registered competition age, Q1 comprised 28.3% and Q4 19.7% of competitors, against population baselines of 24.6% and 22.9% ( $${\chi }^{2}=79.9$$ , $$p<{10}^{-15}$$ , Cohen’s $$w=0.10$$ ). The Q1/Q4 ratio of 1.44 showed no upward age trend through 25 (range 1.36–1.75), and restricting the analysis to ages 13–25, where birth-date coverage is 89–99%, gave the same conclusion. Logistic regression did not support the cumulative-advantage prediction in females ( $${\beta}_{age}=-0.007$$ , $$p=0.46$$ ), showing only a mild curvilinear elevation in males peaking at age 18–19 ( $$p=1.0\times {10}^{-5}$$ for the sex $$\times$$ age interaction). First-year retention from age 10 was nearly identical across quarters (Q1–Q4 gap 2–3 pp), confirming the skew was not produced by differential dropout within the registry. Findings were robust to exclusion of the COVID-19 pandemic years. In a population-wide individual sport without team selection, the birth-quarter skew is established by age 10 and stable through senior level. This pattern is inconsistent with the cumulative-advantage prediction and points to pre-entry selection. I hypothesise that mastery experience through measurable personal progress retains surviving athletes, a feature less available in team-sport contexts. These findings support directing, and evaluating, efforts to reduce relative-age-related participation inequities at the sport-entry transition rather than only at adolescent talent-identification stages; testing this account in other individual sports and countries is a priority.
Source: Sports Medicine - Open
Author: Atle G. Guttormsen
Institution: Norwegian University of Life Sciences
Language: English
Subfield: Developmental and Educational Psychology
Field: Psychology
Domain: Social Sciences
Open Access status: gold
Estimated APC paid: $4,290
OpenAlex ID: W7165161236