Communication and information sharing is a critical part of design and development. Collaboration by a team depends on the creation and dissemination of information. A communication model, such as the one developed in this dissertation, describes when, what, and who communicates different forms of information and could help process engineers and information system (IS) designers to enhance collaboration. The model describes the cognitive modes of a group (the particular, purposeful ways of thinking, used by teams during collaboration), the communication roles of individuals in a group, and effective sense-making forms for groups. Data analysis for this dissertation applied sense-making methodologies (Dervin, 1977), models of cognitive modes during collaboration activities (Smith, 1994), and boundary-spanning communication roles that support "contested collaboration" (Sonnenwald, 1996). Specifically, data was collected and analyzed from several software projects: an expert system after it had been completed and a set of telecommunication applications as they were designed and developed. Furthermore, because the projects spanned seven years (1991-1998), data included computer-mediated communication that ranged from email exchanges to information distribution involving the internet (web pages and hypertext linking). The resulting model shows the forms of communication across the varied cognitive modes and communication roles that software engineers use when they collaborate during design and development projects. Roles and modes can be seen as inter-related through the use of sense-making interfaces to information systems. In summary, the model presented in this dissertation can be used to show when communication can be facilitated in a development phase, what mediating devices appropriately support cognitive modes during collaboration, and who in terms of boundary-spanning roles provides essential communication in a product design environment.