The biorhythm theory of accident explanation that has been increasingly popularized in the business press was empirically examined. The data set consisted of municipal employees adjudged to be at fault in I50 work-related vehicular accidents, and municipal employees involved in 2 10 on-the-job accidents resulting in workmen's compensation claims. Each accident case was analyzed to determine whether or not the accident occurred on a biorhythmically critical day. The results showed no systematic relationship between critical days and accident occurrences for these data groups. The data were also systematically evaluated for the existence of non-biorhythmic cycles. The results of this analysis showed that no useful level of association existed for any cycle. It was concluded that, while other groups or events may exhibit measurable cyclical patterns, it seems likely that the relationships are more complex than a simple association such as that posited on the basis of biorhythm theory. FEW of us would deny that we have good days and bad days-"up" days when everything goes right, and "down" days when nothing we do seems to make any sense. Man has long observed and puzzled over this phenomenon; even Hippocrates, some 2,400 years ago, advised his associates to pay close attention to the "good" and "bad" days among both the sick and the healthy, and to consider these fluctuations in treating their patients (Luce, 197 1). Since those early observations, significant scientific attention has been devoted to identifying and exploring the ramifications of the various cycles inherent in virtually every form of life. Much of this work has been directed to studying cycles occurring within the context of the relatively short 24-hour solar and 24.8 hour lunar (i.e., circadian) periods. However, recent business
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.