- Comparison measures include both subjective measures (based on self-report) and objective measures (based on direct measurement).
- Self-reported measures can be self-administered or interviewer administered, both in person or on the telephone.
- Objective measures include markers of movement (accelerometers), physiological responses that are affected by physical activity (heart-rate), direct measures of energy expenditure (doubly labeled water), and observed or video-taped activity (direct observation).