von Hippel became very interested in this phenomenon and how it worked, and this has guided his research path for many years. Early in his research career, von Hippel was strongly influenced by the work of Nathan Rosenberg of Stanford University, whose research looks at the economics of technological change, and the economic role of science, as well as economic history and development. He was also importantly influenced by Professor Richard Nelson of Columbia University, who has focused on the processes of long-run economic change, with particular emphasis on technological advances. An additional important early influence was Professor Ann Carter of Brandeis who used input-output tables as a central tool in her research, and specialized in the economics of information, technical change, and technology transfer. More recently, a central source of influence and inspiration for von Hippel has been colleagues in the Open and User Innovation Society (OUI). This academic society, now with a membership of hundreds, focuses on research related to innovation processes by users, and the open sharing of innovation via innovation commons. Additional information In an interview with Eric von Hippel, he stated that his favorite aspects of his job were research with colleagues, and doctoral students. He has said his favorite form of research is to develop and test new hypotheses based upon first-hand field observation of newly emerging patterns of innovation practice. In his leisure time, Hippel enjoys chatting with people from many walks of life, and spending time with his family. His wife Jessie is an editor of scholarly books and journal articles and also a tennis player. His daughter Christiana received her ScD from the Harvard T. H. Chan School of Public Health in 2018. She studies health-related user innovations with an emphasis on behavioral innovations. His son Eric James graduated from Emerson College in Media Studies and is in real estate management. When Eric von Hippel's daughter Christiana was young, he often made up cat-related bedtime stories for her because cats were her favorite animal. When she was fourteen, they wrote these stories down and called them "Christiana in Catlandia". They then posted the stories on the web, in hopes that other children would enjoy them too See also Lead user Patient Innovation Private-collective model of innovation User innovation References External links UserInnovation.dk The largest resource center for user innovation Eric von Hippel's homepage at MIT. OpenInnovators.de - die erste Community zu