Mobile data: Made to measure
Nature.com - 11/04/2015
Any effort to establish standards must address two critical questions. How accurate are the readings from these devices? And what exactly is being measured? Today’s fitness trackers are designed to tell users whether they have walked more this week than last week, say, not to collect laboratory-quality measurements. “What they know is general movements, which they try to convert to steps, some better than others,” says Stephen Intille, who studies personal health informatics at Northeastern University in Boston, Massachusetts.