When organizations develop complex information systems, a multitude of actors representing different areas of competence cooperate. These actors refine a set of fuzzy requirements into a concrete artifact through a series of activities producing increasingly detailed systems descriptions. Some of the problems we experience in complex system development stem from the simple fact that the actors misunderstand each other. The aim of this paper is to investigate the frequency and possible impact of misunderstandings between actors in the development of complex information systems. The results are based on the analysis of data collected during a two-day workshop session and a quantitative survey. Our findings show that misunder-standings are considered frequent between all types of actors and are a source of disturbances in the systems development process of complex information system products.