  Avoiding harm is an uncontroversial aim of personalized medicine and other
epidemiologic initiatives. However, the precise mathematical translation of
"harm" is disputable. Here we use a formal causal language to study common, but
distinct, definitions of "harm". We clarify that commitment to a definition of
harm has important practical and philosophical implications for decision
making. We relate our practical and philosophical considerations to ideas from
medical ethics and legal practice.
