Why pathway analysis matters
Every association in data travels along at least one directed path. Knowing which paths exist — and how many — reveals what interventions are structurally possible, where back-door confounders enter, and whether a proposed causal claim is plausible given the graph.
A single short path means a direct, mechanistic effect with few mediators to dilute it. Multiple paths mean an intervention on the source produces simultaneous effects through distinct mechanisms, each potentially with different magnitude and timing. This tool is the prerequisite for every other query: before asking how much X affects Y, you need to know through what routes the effect travels.