Identification of standard mediated effects such as the natural indirect effect relies on heavy causal assumptions. By circumventing such assumptions, so-called randomized interventional indirect effects have gained popularity in the mediation literature. Here, I introduce properties one might demand of an indirect effect measure in order for it to have a true mediational interpretation. For instance, the sharp null criterion requires an indirect effect measure to be null whenever no individual-level indirect effect exists. I show that without stronger assumptions, randomized interventional indirect effects do not satisfy such criteria. I additionally discuss alternative causal interpretations of such effects.

翻译：标准中介效应（如自然间接效应）的识别依赖于较强的因果假设。通过规避此类假设，所谓的随机干预间接效应在中介效应文献中逐渐流行。本文提出间接效应度量应具备的性质，以使其具有真正的中介解释。例如，尖锐零假设准则要求，当不存在个体层面的间接效应时，间接效应度量应为零。研究表明，在没有更强假设的情况下，随机干预间接效应并不满足此类准则。本文还进一步讨论了这些效应的替代因果解释。