David Bassett’s primary research area is the measurement of physical activity and energy expenditure in humans, using objective methods. He and his colleagues study the validity and reliability of pedometers, activity monitors, and fitness trackers, with a particular focus on standardizing daily step counts. In some of these studies, direct observation of steps and a digital hand-tally device are used as the gold standard. In others, a GoPro camera mounted to a chest harness and pointed down a...