A multi-disciplinary study to comprehensively measure and analyze operational performance and indoor environmental conditions in a sample of typical, commercial office buildings in the United States is described. The study will provide data that are currently not available. The indoor building factors that will be investigated during this study have never been formally studied in a comprehensive and systematic manner. No normative database currently exists for typical buildings making it impossible to correlate occupant indoor environmental response data to corresponding building design information and related measured microbiological and engineering data. These data are necessary to properly assess building performance.