In situ and operando techniques have revolutionized electrochemical research by enabling direct interrogation of electrochemical interfaces. However, these methods introduce new failure modes, including experimental perturbations, observability bias, and interpretive overreach, that can yield internally consistent yet misleading conclusions. In this work, we analyze why operando measurements can disagree across techniques, cell configurations, and laboratories despite high data quality. Through a framework examining observability, kinetics, spatial heterogeneity, and inference logic, we show how thin-layer geometries, reference instability, bubble dynamics, probe perturbations, and spectator-dominated signals decouple measured signals from catalytic events. A fundamental paradox emerges: kinetically important intermediates can be unobservable, while spectroscopically dominant species may reflect accumulation rather than catalytic control. We identify interpretive traps recurring across spectroscopic, microscopic, and scattering approaches to establish clearer boundaries for what operando studies can determine and promote rigorous links between observation and mechanistic inference.
Weiran Zheng (Fri,) studied this question.