Heaping in Anniversary Reaction Studies: A Cautionary Note

Abstract

Several studies have reported evidence that death is often associated with significant ceremonial events like holidays and birthdays, a phenomenon variously called the “anniversary reaction,” “holiday effect,” “birthday blues,” etc. This article, using data from the social security death index (SSDI), shows how evidence for this phenomenon can arise from an artifact in death records called “death heaping” in which certain dates, usually the 1st or the 15th, are systematically entered for missing data. In this study, each calendar birthday for the year 2003 in the SSDI was paired with either the 14th or 15th calendar day of death. For each pairing, there were more deaths for the 15th than the 14th. A second analysis compared the correspondence between dying on the same day of the month as one's birthday for the first 28 days of the month. A significantly greater number of birth-death combinations occurred for the 1st and 15th day of the month. These results suggest that studies of “anniversary reactions” should conduct preliminary evaluations to consider the possibility that statistically significant relationships do not arise from “death heaping.”