It is widely accepted that presenting data in the form of pictures or models can enhance comprehension, decision making and communication of the underlying information. However, there are few systematic studies that examine whether graphical models are more effective than other representation (such as textual descriptions). Process models provide an abstract graphical view of organizational procedures by reducing the complex reality of the work performed by a company to its most important activities. Such models are useful to train new employees, to document and allow improving organizational procedures and policies. This paper describes an experiment to address if there are significant differences in terms of process understand ability depending on whether textual work instructions or process models are used to represent a business process. We compared a control group of subjects that received textual work instructions to a second group, which received process models, in terms of their ability to understand the process. We found empirical support that using textual work instructions or process models do not influence process understand ability for non-expert users but do influence for experienced users.