An epistemic account of constitutive relevance lists the criteria by which scientists can identify the components of mechanisms in empirical practice. Three prominent claims from Craver form a promising basis for an account. First, constitutive relevance is established by means of interlevel experiments. Second, interlevel experiments are executions of interventions. Third, there is no interlevel causation between a mechanism and its components. Currently, no account on offer respects all three claims. I offer my causal situationist account of constitutive relevance that (...) respects the claims. By situating a part of a mechanism on the causal chain between the mechanism’s input and output, components can be identified with interventions, without the interventions suggesting interlevel causation. The causal situationist account is the only account on offer so far that clearly fits within Craver’s framework. (shrink)