Resources for Causal Reasoning in Health Services Research

Attribution in causal reasoning

I was presenting on the causal perspective in CER today, and a question came about connection between the claim that deaths are attributed to exposure and the claim that these deaths could be avoided had the exposure been eliminated.

This connection comes from a tradition in epidemiology to use word ‘attribute’ in the meaning ‘regard as resulting from a specified cause’. For example, the population attributable fraction is the proportional reduction in population mortality that would occur if exposure were reduced to an alternative level (eg. no tobacco use).

The argument from epidemiology textbooks (Miettinen, 1974; Greenland, 1984) is as follows. If a population is subject to a harmful exposure (e.g. agricultural pesticides) causing health effects, then we would expect that the overall number of health effects would decline if the exposure is removed (e.g. by policy). The proportional reduction in the number of health problems as a result of removing exposure is known as the “attributable fraction”. In other words, it is the proportion of all health problems (e.g., deaths) in the population that can be attributed to the exposure, i.e., regarded as resulting from it.