The indoor environmental conditions at 1865 workstations from over 60 modern office buildings were studied as part of an integrated Post Occupancy Evaluation study. The offices were located in research and development, public, private, and commercial buildings. Measured IEQ data and occupant responses were correlated with human factors such as age, gender, and spatial factors such as workstation location and its degree of enclosure. The study focuses on identifying the impacts of IEQ on self-reported work productivity.