Citation

Sass TR, Leigh JP. Rev. Econ. Stat. 1991; 73(1): 167-172.

Copyright

(Copyright © 1991, Department of Economics, Harvard University, Publisher MIT Press)

DOI

10.2307/2109701

PMID

unavailable

Abstract

Existing econometric studies of the efficacy of motorcycle helmet laws assume that such laws are exogenously determined and may therefore yield biased results. To correct for possible selectivity bias, we specify and estimate a self-selection model in which the choice of having a helmet law is endogenous. Our results indicate selectivity bias exists and that if laws were randomly assigned, fatality rates for states with helmet laws would on average be less than 1% lower than for states without laws.