This dissertation presents an inquiry into the roles played by persistent, shared external
representations in design collaboration. It advances an understanding of the active
participation of these representations—including drawings, models and prototypes—in the
collective reasoning of design teams. Interaction was analyzed using a novel network
formalization to portray the accomplishment of essential work in this context. A synthesis
of analyses over different time scales provides the basis for a comprehensive notion of
representational support for design interaction, and a diagnostic for problems that may arise
with inadequate support and/or disparities of access and participation.
Data were collected during working sessions of a leading, “real-time” concurrent design
practice at NASA’s Jet Propulsion Laboratory, notable for accelerated performance and the
use of technologically-advanced, shared representations. Fine-grained analysis of this
activity offers insights to complement those obtained from laboratory studies of individual
designers, ad-hoc groups, and organizationally-situated ethnographic accounts. A microanalytic
technique was developed to assess dynamic interaction between participants and
representations. The resulting, novel formalization of an actor-discourse network makes
concepts derived from actor-network theory operational to understand the work
accomplished through design interaction. Network visualization and structural metrics
highlight patterns associated with productivity in the design process. On this basis,
indicators for the quality of design conversation are proposed: these include the degree of
participants’ engagement, the development of design discourse, the integration of
representations and the consolidation of commitment to action. Specific roles and
situational attributes of representations are identified that foster and sustain advances in
collective design reasoning.
The dissertation advances a view of design activity in terms of temporally-evolving
constellations of issues and actors, in which representations act to stabilize and anchor
expanding networks of commitment. Directions for further work include technical
enhancement to network metrics and visualization, extension of the actor-discourse network
formalization and further exploration of theoretical and practical issues pertaining to
representational actors in social situations.