Massive Individualized N-of-1 Experiments Using HackYourHealth: A New Paradigm for Promoting Health and Well-Being

N-of-1 trials (single patient crossover experiments) are a uniquely powerful technique for estimating treatment effects in the individual. N-of-1 trials have been offered to hundreds or perhaps thousands of patients worldwide, but never at scale. HackYourHealth is a tool that supports the conduct of simple N-of-1 self-experiments to test if healthy activities that work in general (i.e., mindfulness meditation, physical activity, gratitude journaling, random acts of kindness, and laughter therapy), improve psychological well-being (stress, focus, happiness) in specific individuals. The tool supplies the experimental design, facilitates data analysis, and channels feedback to participants. The tool is flexible enough to support Massive Individualized N-of-1 Experiments (MINEs) at scale. Working with WNYC Radio in New York City, we will recruit and run 18-day N-of-1 trials up to 10,000 individuals. The purpose of this study is to conduct a formative evaluation of HackYourHealth in terms of its perceived usefulness and to explore heterogeneity in intervention response across the sample. We anticipate that the results will: 1) identify useful behavioral interventions for individual participants; 2) help to estimate generalizable treatment effects for the interventions of interest; 3) assess heterogeneity of treatment effects across subgroups; and 4) elucidate the user experience with N-of-1 trials. When complete, the study will support additional proposals designed to assess the utility of MINEs as applied to additional conditions and treatments.