Birth Dates and Death Dates: An Examination of two Baseline Procedures and Age at Time of Death

Abstract

The present study continues analyses of variations in the frequencies of death in the near temporal proximity of decedents' birthdays. Observed frequencies were compared with expected frequencies as ascertained from two baseline distributions. One distribution was the usual rectangular distribution, based on summing the number of deaths across all frequency categories and then dividing by the number of categories. The other distribution was constructed by pairing one person's birth date with another person's death date. This latter distribution was intended to provide a true baseline, and provide a better gauge for assessing the likelihood that any obtained relationship reflected coincidence or chance. Two weeks before and two weeks after the birthday there were more deaths, and one week after the birthday there were fewer deaths, than would be expected on the basis of either baseline distribution. Day-by-day analyses within the birthweek confirmed earlier reports of high followed by low frequencies of death. Compared to relatively old men, relatively young men were more likely to die on the eve of their birthdays or on their birthdays themselves. Compared to relatively young men, relatively old men's death dip begins at an earlier point in time. Methodological and theoretical implications are discussed.