Citation

Elvik R. Accid. Anal. Prev. 2011; 43(3): 1245-1251.

Affiliation

Institute of Transport Economics, Gaustadalléen 21, NO-0349 Oslo, Norway.

Copyright

(Copyright © 2011, Elsevier Publishing)

DOI

10.1016/j.aap.2011.01.007

PMID

21376924

Abstract

This paper shows that the meta-analysis of bicycle helmet efficacy reported by Attewell, Glase, and McFadden (Accident Analysis and Prevention 2001, 345-352) was influenced by publication bias and time-trend bias that was not controlled for. As a result, the analysis reported inflated estimates of the effects of bicycle helmets. This paper presents a re-analysis of the study. The re-analysis included: (1) detecting and adjusting for publication bias by means of the trim-and-fill method; (2) ensuring the inclusion of all published studies by means of continuity corrections of estimates of effect rely on zero counts; (3) detecting and trying to account for a time-trend bias in estimates of the effects of bicycle helmets; (4) updating the study by including recently published studies evaluating the effects of bicycle helmets. The re-analysis shows smaller safety benefits associated with the use of bicycle helmets than the original study.

Language: en