We noted with considerable interest Leon Robertson's article (1976), in a recent issue of this journal, dealing with statistical measures of the effectiveness of helmet and daytime headlight laws for motorcyclists. For some time, proponents and opponents of such legislation have been trading enthusiastic arguments and impassioned denials, often including misleading statistical presentations. The result has been that most followers of this debate are left with their personal views and little in the way of substantive support for either side. Robertson uses what appear to be promising data bearing on the safety controversy but, in our view, he does not perform the analyses required to clear the muddled waters and he seriously misinterprets the statistics he employs.