Kayleigh Campbell is a doctoral student in sustainable development at the School of International and Public Affairs at Columbia University. In her dissertation research she is analyzing the impact that bike sharing has had on subway, bus, and taxi ridership and efficiency in New York City using a differences-in-differences research design. The goal is to learn more about how bike sharing interacts with other modes of transportation. She is also studying transportation access in Nairobi. Using data from the Digital Matatus Project, she and her collaborators are trying to understand where and to whom transportation access is provided and how to appropriately measure access in a developing country context. Finally, in her master’s research she found that U.S. cities that had urban rail transit before the automobile age, have lower per capita carbon dioxide emissions today than cities built entirely around the automobile. She loves exploring new ideas and playing with data. Her biggest research challenge has been tracking down the data she needs for those ideas!