[Dictionary] Reverse Causality

Reverse causality (also called reverse causation) is the error of assuming a relationship between two variables, X and Y, runs from X to Y when the true causal arrow runs the opposite way -- from Y to X -- or, in the general case, runs both ways at once as a feedback loop. It requires no third variable: the mistake is not that some lurking factor is driving both X and Y (that is confounding), it is that the direction assigned to a real relationship between X and Y is simply backwards. Observing that X and Y are correlated, or even that X was measured before Y, does not establish that X causes Y -- it is equally consistent with Y's own prior trajectory having produced X, which is common whenever both variables are stable traits or slow-moving processes capable of influencing each other over time.