Leif's current research interest focuses primarily on customer online word of mouth. In this work, he uses econometric methods to analyse company data. A second line of research relates to the performance effects of information transparency in organisational and sales contexts. In the past, Leif has also conducted a number of studies in the field of individual judgment and decision-making. Leif's work has appeared in internationally renowned journals such as Management Science, European Economic Review, Marketing Letters, Journal of Economic Behavior and Organization, European Journal of Marketing, and others. He holds a PhD from University of Zurich, Switzerland and was a postdoctoral fellow for six months at the Yale School of Management, Yale University. Leif also holds a Master in Mathematical Finance from the University of Konstanz, Germany.