Marcel Boumans is historian and philosopher of science at Utrecht University. His main research focus is on understanding empirical research practices in economics from a philosophy of science-in-practice perspective. He is particularly interested in the practices of measurement and modeling and the role of mathematics in social science. Because models are not complete as sources of knowledge for sciences outside the laboratory, additional expert judgements are needed. His most recent research focuses on vision and visualization, that is exploring how expert judgments are made by studying practices of visualizations..