Florian Keusch is an Professor of Social Data Science and Methodology at the School of Social Sciences, University of Mannheim, Germany, and an Adjunct Research Professor at the Joint Program in Survey Methodology, University of Maryland. Before joining the Universities of Mannheim and Maryland, he was a Research Fellow at the Institute for Social Research at the University of Michigan. He received a PhD in Social and Economic Sciences (Dr.rer.soc.oec.) and a MSc in Business (Mag.rer.soc.oec.) from WU (Vienna University of Economics and Business), Austria. His research interests include nonresponse and measurement error in Web and mobile Web surveys, passive mobile data collection, and visual design effects in questionnaires.