Is it correct to use 'indirect effect' and 'mediation' interchangeably in all situations? I mean if we know that A influences B and B influences C. Can we conclude that the effect is mediated by B without performing a mediation test?
Solved – Is ‘indirect effect’ the same as ‘mediation’
mediationterminology
Best Answer
No, "mediation" and "indirect effect" are not synonymous. For example, when analyzing complex causal systems in which any variable in the system at time $t$ contributes causally to every variable in the system at times $>t$, the term "mediator" is largely meaningless, whereas indirect effects may or may not exist due both to the qualitative structure of the system, and due to the quantitative magnitude of direct causal effects withing that structure (see, for example, Levins, R. (1974). The qualitative analysis of partially specified systems. Annals of the New York Academy of Sciences, 231:123–138.)
gung's answer assumes a terminal causal model, where the analysis attempts to explain or predict a final causal outcome, typically in a limited set of variables. By contrast complex causal models attempt to explain system behaviors.