Validity of the EPIC questionnaire physical activity categories compared to accelerometer measurement. Box-and-whisker plots describing the validity of European Prospective Investigation into Cancer and Nutrition questionnaire physical activity categories compared to accelerometer measurement of total activity. The box represents the median and interquartile range, and the bars indicate the range. Graphs are presented for accelerometer MET-hours/week by: A. total physical activity index (Spearman rank correlation ρ = 0.29, 95% CI 0.15, 0.42), B. Cambridge physical activity index (0.32, 95% CI 0.19, 0.45), and C. occupational physical activity level (0.37, 95% CI 0.22, 0.51, excluding non-workers). P < 0.0001 for all measures.