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:在调解文献中,通过规避这些假设,所谓的随机干预间接效应已受到欢迎。这里,我介绍人们可能要求采取间接效应措施的属性,以便它得到真正的调解解释。例如,尖锐的无效标准要求,如果不存在任何个人层面的间接效应,间接效应措施即为无效。我表明,如果没有更强烈的假设,随机干预间接效应无法满足此类标准。我还要讨论对此类效应的替代因果解释。