Effects of a rule change that eliminates body-checking on the relative age effect in Ontario minor ice hockey
Bibliographic record
Abstract
Relative age effects in sport reflect an over-representation of athletes born early in a selection year that lead to selection and performance advantages. These effects might be enhanced by rules that increase physicality. An opportunity to investigate these influences arose when Hockey Canada altered its body-checking rules. Two studies are described that investigate the possible influence of this rule change. Study 1 used cross-sectional data to contrast relative age effects for 9-year-olds in games with and without body-checking (birth quartile 1 ranged from 27 to 39%; birth quartile 4 from 10 to 20%). Study 2 used quasi-longitudinal data to examine age effects when players transitioned from a season in which body-checking was permitted to one that prohibited such checking (birth quartile 1 ranged from 27 to 39%; birth quartile 4 from 11 to 20%). Chi-square statistics demonstrated relative age effects in both studies irrespective of body-checking. Post-hoc analyses indicated reductions in these effects that were limited to some second and third quartiles when body-checking was prohibited. Body-checking is not a critical mechanism of relative age effects. The physicality of ice hockey, regardless of body-checking, and increased experience in ice hockey are influential.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.011 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".