A decade ago, smartphones were used by a small fraction of adults globally and rarely used to respond to surveys. Today, by comparison, smartphone use is widespread in many countries, and growing proportions of survey participants are choosing to respond to Web surveys on their mobile devices. In light of this change, survey researchers have begun examining ways to optimize the design of mobile surveys to improve data quality. This webinar will discuss how their findings can inform design choices about screen layout and question formatting. Specific topics will include radio button size, text versus voice input for open items, grids, drop boxes, and scrolling versus paging question grouping. The webinar will also highlight some unresolved questions and directions for future research.