When better data meets better design: How EHR data usability and system usability shape physicians’ cognitive load

Electronic health record (EHR) systems were designed to enhance clinical decision-making, yet the way data is organized and displayed can create significant cognitive demands for physicians. This study examines how EHR data usability (data quality, data completeness, and data-driven use) and system usability jointly shape physicians' cognitive load. Using survey responses from 564 physicians across 32 specialties, we tested a mediated model with covariance-based structural equation modeling. Reliability and validity were assessed through standard psychometric criteria. Findings show that stronger data usability increases germane cognitive load, promoting deeper engagement with clinically meaningful information. In contrast, higher system usability reduces extraneous cognitive load by aligning interface design with clinical workflow and minimizing navigation-related effort. Information overload partially mediated these effects, suggesting that better data usability helps physicians better filter irrelevant data and stay focused on diagnostically relevant cues. Overall, the results highlight two levers for improving cognitive performance: enhancing system usability lowers unnecessary cognitive effort and documentation-related errors, while improving data usability supports reasoning-intensive diagnostic work. Optimizing both fosters balanced cognitive load and more sustainable, error-resilient clinical decision-making.