A novel way to conduct human studies and do some good

In this paper the authors describe a novel way to conduct large-scale human studies achieving the maximum outreach and impact with the minimum cost. An iPhone health application, 'Walk n' Play', was developed and released for free in the App Store. The application measures calories spent due to walking activities through the iPhone's accelerometer. It is a real-time awareness tool that helps people to keep their sedentariness in check. Furthermore, it uses motivational mechanisms based on buddy support/competition and social networking to increase daily physical activity. The anonymous data gathered from thousands of users around the world, reveal patterns of human behavior at a resolution and scale not feasible before.