The flow model by Beyer and Holtzblatt (1998) is a useful diagrammatic work model for representing the people in work activities and their communication paths for user-centred design. However, to represent a large complex team using a single flow model may result in visual complexity that hinders visual understanding. In this paper, we propose an approach of using sub-flow models to address this problem and contribute a set of guidelines to facilitate the construction of sub-flow models. Each sub-flow model captures a slice of the work activities and the collection of sub-flow models captures the whole of the work activities. We found that sub-flow models not only helped to reduce visual complexity, it also provided a gradual and guided way to progressively increase one’s understanding about the work activities.

Keywords: Sub-flow model, Work model, Activity model, User model.