Dr. Gabbard's work centers on human factors and human-computer interaction; specifically perceptual and cognitive issues related to user experience and usability engineering of novel user interfaces including 3D visualization and interaction in augmented and virtual environments, multimodal interactive systems, and visualizations for life sciences. As a pioneer in usability engineering with respect to applying and creating methods for new interactive systems for more than 19 years, Dr. Gabbard has conducted numerous user-studies in augmented reality examining human performance and safety in applied (usability engineering) and basic science domains (color perception, occlusion, depth perception). He was the lead user experience engineer of one of the first mobile head-worn AR systems (the Battlefield Augmented Reality System). More recently, he has been focusing his research on human performance, natural user interaction, situational awareness and safety associated with AR displays in transportation, military, manufacturing, building & construction domains.