Substitution of Method in Suicide and Homicide: A Regional Analysis
Lester ( 1) found that, over time, homicide rates by each of several methods correlated positively, while suicide rates by hanging and residual methods correlated negatively with suicide rates by firearms and poisoning. In suicide, as one method becomes less popular, other methods become more popular. The present srudy was designed to check these ideas across the states to see whether ecological correlations gave a similar pattern to time series correlations. Suicide and homicide races by each method were calculaced for 1970 for each of the 48 continental United States from data published in the Vital Statistics of the Uqzited States ( 2 ) . For 1970, the three rates of homicide (by firearms and explosive, cutting and piercing and other means) were all positively associated (Pearson rs = 0.76, 0.46 and 0.53), and each of these three homicide rates correlated positively with the total homicide rare (rs = 0.99, 0.84, and 0.57). However, for suicide, a different pattern emerged. The suicide rates by poisons, hanging/strangulation and other methods all correlated positively (rs = 0.41, 0.38, and 0.25), but two of these three rates correlated negatively with the suicide rate by firearms (rs = 0.19, -0.32, and -0.45, respectively). Only the suicide rates by poisons and by firearms correlated with the total suicide race (rs = 0.72 and 0.80, respectively). For suicide then, there appears to be a tendency for people in different regions to use one method or another. The more firearms and poisons are used, the less hanging and ocher methods are used. These results paraIlel the time series results quite closely.