Do sibling comparisons answer the causal question? In response to ‘No causal associations between childhood family income and subsequent psychiatric disorders, substance misuse and violent crime arrests’

The recent paper by Sariaslanet al.1 on the causal impact of childhood family income has gained attention in the field of social medicine. And rightfully so, as it is a comprehensive, well-conducted and important piece of epidemiological work. It is also one of few instances in which a precise null-finding may have important political implications. Quoting the authors: ‘An important implication of our findings, if replicated in other contexts, is that interventions that primarily focus on improving parental earnings will unlikely lead to reductions in rates of psychiatric disorders, substance misuse and violent arrests in their offspring.’ We applaud Sariaslanet al. ’s ambition to estimate causal effects, but we question whether the employed sibling design can inform the causal question that is being raised (and supposedly answered), namely whether there will be an effect of intervening on family income.
Source: International Journal of Epidemiology - Category: Epidemiology Source Type: research