Adequacy of official suicide statistics for scientific research and public policy

Many researchers have claimed that the study of suicide and the formation of public policy are not undermined by the misclassification of suicide as other causes of death. We evaluated this claim using a new technique and causes of death not previously considered. We examined computerized California death certificates, 1966-1990. Mortality peaks at symbolic ages are a characteristic feature of suicide. We sought such peaks in (1) causes of death commonly suspected of containing misclassified suicides (e.g., accidental barbiturate poisoning), (2) causes of death not hitherto suspected (e.g., pedestrian deaths), and (3) control groups. The first two categories displayed peaks at symbolic ages, but control groups did not. The size of the peak, indicative of misclassified suicides, varied markedly by race (p < .0001) and sex (p < .0001). Misclassification is evident for all time periods examined, large and small counties, and each race and sex. The maximum misclassification occurs for Blacks (14.92% of officially recorded suicides). We conclude that suicides are misallocated to at least five other causes of death (two of which have not been previously considered in the literature) and are most likely to be underreported for groups with low official suicide rates, that is, Blacks and females. Consequently, Blacks and females are not as protected from suicide as was previously supposed. It may be inadvisable to use official suicide data to test scientific hypotheses about suicide, unless the effects of underreporting are estimated and, if necessary, corrected for.