Elicitation and validation of user requirements depend, to a large extent, on the effectiveness of the tools and techniques used as a vehicle for discussion between developers and users during the requirements process. This effectiveness may, in turn, be influenced by user preference for a particular approach or requirements technique. This paper describes a study that was carried out to investigate the relationship between user preference for sequence or collaboration diagrams in UML, with their accuracy in understanding information contained in the diagrams. Results showed that user preference for one of the two diagram types before carrying out the task was not reflected in improved performance with that type of diagram compared with the other. However, after carrying out the task, user statements about which type of diagram they preferred working with were matched by improved performance with that type of diagram