Abstract
Over the past fifteen years, infectious disease surveillance has evolved to include online citizen science projects that implement active digital data collection. Flu Near You (FNY) is an online participatory surveillance system in the United States that collects weekly health reports from its volunteers. Because high engagement levels and consistent participation of users are essential to accurately track disease and estimate burden, FNY implemented three measures: (1) adding a new feature in that allows website visitors to submit a health report without registering, (2) administering user surveys at the end of each influenza season, and (3) partnering with Science Friday (SciFri) (a weekly public radio program that discusses topics relevant to science, nature, and technology) with the goals of increasing the number of weekly participant reports, improving the frequency of user reporting, and understanding user motivation. In this paper, we evaluate the impact of these three measures. The number of registered users who submitted only one report decreased after allowing users to submit reports without registering. The survey indicated that respondents were primarily motivated by the importance of disease tracking and by a desire to participate in a citizen science project. Finally, users who registered from SciFri were highly engaged and also motivated by a desire to participate in a citizen science project.