1 Postdoctoral research fellow at the University of Michigan, Department of Statistics.
2 Graduate student at the University of Michigan, Department of Statistics.
3 Assistant professor of information, School of Information, and assistant professor of health behavior and health education, School of Public Health at the University of Michigan.
4 Research assistant professor at the Survey Research Center, Institute for Social Research, University of Michigan.
5 H.E. Robbins Distinguished University Professor of Statistics, professor of psychiatry, and research professor, Institute for Social Research at the University of Michigan.
Data from activity trackers and mobile phones can be used to craft personalised health interventions. But measuring the efficacy of these "treatments" requires a rethink of the traditional randomised trial.