Pathway Analysis, Causal Mediation, and the Identification of Causal Mechanisms

Abstract

AbstractThis chapter presents the systematic analysis of causal mechanisms from the perspective of pathway analysis as an essential complement to conventional approaches to causation. It builds on the evidence that credible causal identification defies design-based strategies such as randomization or linear mediation analysis unless their research designs are supported by reliable mechanistic knowledge. The chapter reasons that the reliable causal identification of a mechanism requires the concept of ‘natural indirect effect’ and a double-nested counterfactual strategy. It discusses the empirical quantification of causal mechanisms and its underlying assumptions, offers empirical examples that clarify them, and reviews the conditions and limits of the strategy.