As smartphone penetration continues to increase around the world, survey researchers are exploring novel ways to leverage the capabilities of smartphones for data collection beyond self-reports. Researchers can now administer survey questions on the smartphone and, at the same time, ask respondents to perform tasks such as taking pictures, recording audio and video, and granting access to data from built-in sensors and log files. Combining these different sources of data promises to produce information not available from either type of measurement alone. In this talk, the presenter will discuss the benefits and challenges of collecting data passively with smartphones within an existing longitudinal survey. The lessons learned in this study provide design suggestions for other large scale surveys planning to integrate passive mobile measurement into the data collection process. Offered in-person and online.