My research lies at the intersection of Human-Computer Interaction and Health Informatics. I study how technology can help people to better manage their health and to more effectively communicate with their healthcare providers. Because a great deal of what people need to do to improve their health—being physically active, eating healthily, taking medications regularly, etc.—happens in the midst of daily life and away from the clinic, one area I study is how technology can help people to adopt and sustain such health-promoting activities. I see mobile technology as a particularly powerful tool for providing this support. Over 60% of U.S. population have smartphones—pocket computers that have an always-on internet connection, are equipped with large number of sensors, and can run sophisticated applications. And these devices are with us all the time. Their technical capabilities and the fact they are always close at hand make mobile phones a perfect platform for supporting health behavior change. I explore the ways in which phones can keep people engaged with their health goals throughout the day, discover opportunities for healthy behavior, and reflect on their behavior patterns to identify ways to improve their health without disrupting relationships and routines that are important to them.