A NEED FOR MORE EXPERIMENTAL STUDIES OF PHYSICAL ACTIVITY DURING CHILDHOOD: RESPONSE
Bibliographic record
Abstract
Dear Editor-in-Chief: We would like to thank Dr. Shephard for his comments on our recent article (1) but wish to clarify a few points raised in his letter. Although we agree that our data would support those who wish to increase school physical activity time, we did not specifically study this point. We looked at extracurricular activities. Our broad definition of organized childhood sports would include both competitive and noncompetitive activities and not just competitive activities as implied in his letter. We agree that confounding by a factor such as enjoyment of or skill at physical activity in childhood, as was mentioned in our article, may have influenced our findings. Although it is likely that sports participation in childhood is not random, increasing the extent to which children participate in sports by giving more children skills and exposure to a variety of sports may increase the level of adult participation in physical activity. We agree that an experimental study to investigate the “childhood intervention” hypothesis would be both difficult and costly. Allen Kraut, M.D. Samuel Melamed, Ph.D. Paul Froom, M.D.
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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 | 0.013 | 0.066 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.002 | 0.002 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.002 | 0.004 |
| Scholarly communication | 0.002 | 0.005 |
| Open science | 0.004 | 0.002 |
| Research integrity | 0.034 | 0.048 |
| Insufficient payload (model declined to judge) | 0.005 | 0.004 |
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".