Reexamining the Ecological Fallacy: A Study in Which Aggregate Data Are Critical in Investigating the Pathological Effects of Living Alone

Social isolation, as measured by living alone, is hypothesized to be a cause of mortality due to suicide and alcoholism. A detailed methodological argument is presented for using aggregate evidence to test this hypothesis. Analysis of data from 389 American cities demonstrates that living alone is strongly related to two types of mortality: suicide and alcoholism. Evidence is presented that the relationships found in these data are not due to social drift, and that there are solid grounds for concluding the relationships are causal.