Successful Scientific Replication and Extension of Levitt (2008): Child Seats are Still No Safer Than Seat Belts
Bibliographic record
Abstract
Summary Using US fatality data from 1975 to 2003, Levitt (Evidence that seat belts are as effective as child safety seats in preventing death for children aged two and up, Review of Economics and Statistics 2008; 90(1): 158–163) shows that child safety seats do not significantly reduce fatalities for children aged 2–6 years as compared to standard seat belts. Although we were unable to gain access to the original programs and dataset used, we were able to replicate Levitt's ( ) findings almost exactly. We extend Levitt ( ) by showing that the findings also hold for the years 2004–2011 despite changing driver characteristics and restraint use patterns. We fail to find evidence that SUVs provide additional safety for children. Copyright © 2015 John Wiley & Sons, Ltd.
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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 | 0.333 | 0.692 |
| Meta-epidemiology (narrow) | 0.002 | 0.001 |
| Meta-epidemiology (broad) | 0.003 | 0.005 |
| Bibliometrics | 0.006 | 0.006 |
| Science and technology studies | 0.002 | 0.007 |
| Scholarly communication | 0.005 | 0.005 |
| Open science | 0.006 | 0.009 |
| Research integrity | 0.004 | 0.006 |
| Insufficient payload (model declined to judge) | 0.010 | 0.003 |
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; the direct Gemma label and the distilled Codex classifier agree on what is shown here.
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".