How to assess the effectiveness of activity trackers for improving health

The rise of wearable activity trackers, such as Fitbit, Fuelband, and Jawbone, has generated a lot of public excitement as well as interest from researchers who are enthused about the opportunities these devices may provide to monitor activity and help people lead healthier lives.

A new article notes that the traditional randomised trial designs used in health and medicine are not well suited to mobile health, and perhaps the "micro-randomised trial" can be a useful alternative. Micro-randomised trials are trials in which participants are randomly assigned a treatment from the set of possible treatment actions at several times throughout the day. Therefore, each participant may be randomized hundreds or thousands of times over the course of a study.

"These trials will provide evidence regarding in which real-time settings wearable devices should provide treatments to help you and me, and in which settings these treatments will only aggravate us," said Dr. Susan Murphy, senior author of the Significance article.