The National Human Exposure Assessment Survey (NHEXAS) studies provide the basis for identifying major predictors of exposure to understand how high exposures can be reduced and how activities contribute to exposures. A systematic analysis of the questions used in NHEXAS relative to environmental concentration and exposure measurements offers an opportunity to minimize participant burden and costs for future exposure and health effects studies. As part of the Strategic Analysis Plan for the NHEXAS study data, task P-01: Analysis and Comparison of NHEXAS Exposure Data to Residential Pollutant Sources, Concentrations, and Activity Patterns was charged with identifying questionnaire items and/or environmental and biological measures that are useful for predicting human exposure to chemicals. Using data from the NHEXAS Region 5 and Arizona studies, this project evaluated such potential relationships under three analysis objectives: modeling and regression analysis, classification of individuals by their exposure level, and classification of individuals with high-end exposure levels. Forty-eight model-based analyses for each of the three objectives were performed. The topics of predictors that seem to be most universal across the two studies and two chemical classes are air measurements, tobacco-related activities, air-exchange activities, housing characteristics, and where time is spent.