Over the past three decades, adolescent emotional problems have risen at an alarmingly rate. One of the biggest changes in young people’s lives over the last few decades has been the parallel rise in digital media use, however, implications for trends in youth mental health remain unclear. Efforts to understand the role of digital media in relation to youth mental health have so far been limited by retrospective self-reports. One way to advance our understanding of digital media is to use ecological momentary assessments (EMA). EMA is a research method that involves real time reports in a real world setting. As such, it provides more objective and fine-grained data about both time and type of digital media use. The current project will test whether built-in features of a smartphone, as well as EMA, can be used to complement our understanding of digital media use among children and adolescents, and the possible impact this may be having on their emotional problems.